configure: Reoder configuration logic

This should make this a bit easier to understand and more readable.
Apart from comments nothing was removed or added, just reodered.

1 files changed, 150 insertions, 137 deletions

diff --git a/configure.ac b/configure.ac
index bbe803a..497e1b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,18 +21,7 @@ AC_CHECK_HEADERS([stdint.h iconv.h])
 # Checks for library functions.
 AC_CHECK_FUNCS([strdup strndup])
 
-# Checks for libraries.
-# Add them to pkg-config for static linking.
-OLDLIBS="$LIBS"
-LIBS=
-use_libiconv=false
-AC_SEARCH_LIBS([libiconv_open], [iconv], use_libiconv=true)
-AC_SEARCH_LIBS([iconv_open], [iconv], use_libiconv=true)
-AC_CHECK_LIB([m], [fabs])
-pkg_libs="$LIBS"
-LIBS="$OLDLIBS $LIBS"
-
-# Check for libraries via pkg-config
+# Query configuration parameters and set their description
 AC_ARG_ENABLE([test], AS_HELP_STRING([--enable-test],
     [enable test program (requires libpng) @<:@default=no@:>@]))
 AC_ARG_ENABLE([compare], AS_HELP_STRING([--enable-compare],
@@ -52,98 +41,18 @@ AC_ARG_ENABLE([asm], AS_HELP_STRING([--disable-asm],
 AC_ARG_ENABLE([large-tiles], AS_HELP_STRING([--enable-large-tiles],
     [use larger tiles in the rasterizer (better performance, slightly worse quality) @<:@default=disabled@:>@]))
 
-AS_IF([test x$enable_asm != xno], [
-    AS_CASE([$host],
-        [i?86-*], [
-            INTEL=true
-            AS=nasm
-            X86=true
-            BITS=32
-            BITTYPE=32
-            ASFLAGS="$ASFLAGS -DARCH_X86_64=0" ],
-        [x86_64-*-gnux32|amd64-*-gnux32], [
-            AS=nasm
-            INTEL=true
-            X64=true
-            BITS=64
-            BITTYPE=x32
-            ASFLAGS="$ASFLAGS -DARCH_X86_64=1 -DPIC" ],
-        [x86_64-*|amd64-*], [
-            AS=nasm
-            INTEL=true
-            X64=true
-            BITS=64
-            BITTYPE=64
-            ASFLAGS="$ASFLAGS -DARCH_X86_64=1 -DPIC" ],
-        )
-    AS_IF([test x$INTEL = xtrue], [
-        AC_CHECK_PROG([nasm_check], [$AS], [yes])
-        AS_IF([test x$nasm_check != xyes], [
-            AC_MSG_WARN(nasm was not found; ASM functions are disabled.)
-            AC_MSG_WARN(Install nasm for a significantly faster libass build.)
-            enable_asm=no
-        ], [
-            AS_CASE([$host],
-                [*darwin*], [
-                    ASFLAGS="$ASFLAGS -f macho$BITTYPE -DPREFIX -DHAVE_ALIGNED_STACK=1" ],
-                [*linux*|*dragonfly*|*bsd*|*solaris*|*haiku*], [
-                    ASFLAGS="$ASFLAGS -f elf$BITTYPE -DHAVE_ALIGNED_STACK=1" ],
-                [*cygwin*|*mingw*], [
-                    ASFLAGS="$ASFLAGS -f win$BITTYPE"
-                    AS_IF([test x$BITS = x64], [
-                        ASFLAGS="$ASFLAGS -DHAVE_ALIGNED_STACK=1"
-                    ], [
-                        ASFLAGS="$ASFLAGS -DHAVE_ALIGNED_STACK=0 -DPREFIX"
-                    ])
-                ],
-                [ #default
-                    AC_MSG_ERROR(m4_text_wrap(m4_normalize([
-                            Please contact libass upstream to figure out if ASM
-                            support for your platform can be added.
-                            In the meantime you will need to use --disable-asm.]),
-                        [                  ],
-                        [could not identify NASM format for $host !],
-                        [78])
-                    )
-                ]
-            )
-            ASFLAGS="$ASFLAGS -DHAVE_CPUNOP=0 -Dprivate_prefix=ass"
-            AC_MSG_CHECKING([if $AS supports vpmovzxwd])
-            echo "vpmovzxwd ymm0, xmm0" > conftest.asm
-            AS_IF([$AS conftest.asm $ASFLAGS -o conftest.o >conftest.log 2>&1], [
-                AC_MSG_RESULT([yes])
-            ], [
-                AC_MSG_RESULT([no])
-                VER=`($AS --version || echo no assembler) 2>/dev/null | head -n 1`
-                AC_MSG_WARN([nasm is too old (found $VER); ASM functions are disabled.])
-                AC_MSG_WARN([Install nasm-2.10 or later for a significantly faster libass build.])
-                enable_asm=no
-            ])
-            rm conftest.asm conftest.o > /dev/null 2>&1
-        ])
-    ])
-])
-
-AC_SUBST([ASFLAGS], ["$ASFLAGS"])
-AC_SUBST([AS], ["$AS"])
-
-AM_CONDITIONAL([ASM], [test x$enable_asm != xno])
-AM_CONDITIONAL([INTEL], [test x$INTEL = xtrue])
-AM_CONDITIONAL([X86], [test x$X86 = xtrue])
-AM_CONDITIONAL([X64], [test x$X64 = xtrue])
-
-AM_COND_IF([ASM],
-    [AC_DEFINE(CONFIG_ASM, 1, [ASM enabled])],
-    [AC_DEFINE(CONFIG_ASM, 0, [ASM enabled])]
-    )
-
-AM_CONDITIONAL([ENABLE_LARGE_TILES], [test x$enable_large_tiles = xyes])
-
-AM_COND_IF([ENABLE_LARGE_TILES],
-    [AC_DEFINE(CONFIG_LARGE_TILES, 1, [use large tiles])]
-    [AC_DEFINE(CONFIG_LARGE_TILES, 0, [use small tiles])],
-    )
+# Checks for available libraries and define corresponding C Macros
+# and add packages to pkg-config for static linking
+OLDLIBS="$LIBS"
+LIBS=
+use_libiconv=false
+AC_SEARCH_LIBS([libiconv_open], [iconv], use_libiconv=true)
+AC_SEARCH_LIBS([iconv_open], [iconv], use_libiconv=true)
+AC_CHECK_LIB([m], [fabs])
+pkg_libs="$LIBS"
+LIBS="$OLDLIBS $LIBS"
 
+## Check for libraries via pkg-config
 PKG_CHECK_MODULES([FREETYPE], freetype2 >= 9.10.3, [
     CFLAGS="$CFLAGS $FREETYPE_CFLAGS"
     CXXFLAGS="$CFLAGS $FREETYPE_CFLAGS"
@@ -157,6 +66,22 @@ PKG_CHECK_MODULES([FRIBIDI], fribidi >= 0.19.0, [
     AC_DEFINE(CONFIG_FRIBIDI, 1, [found fribidi via pkg-config])
     ])
 
+PKG_CHECK_MODULES([HARFBUZZ], harfbuzz >= 1.2.3, [
+    CFLAGS="$CFLAGS $HARFBUZZ_CFLAGS"
+    LIBS="$LIBS $HARFBUZZ_LIBS"
+    AC_DEFINE(CONFIG_HARFBUZZ, 1, [found harfbuzz via pkg-config])
+    ])
+
+libpng=false
+if test x$enable_test = xyes || test x$enable_compare = xyes; then
+PKG_CHECK_MODULES([LIBPNG], libpng >= 1.2.0, [
+    CFLAGS="$CFLAGS $LIBPNG_CFLAGS"
+    AC_DEFINE(CONFIG_LIBPNG, 1, [found libpng via pkg-config])
+    libpng=true])
+fi
+
+## Check for system font providers
+### Fontconfig
 if test x$enable_fontconfig != xno; then
 PKG_CHECK_MODULES([FONTCONFIG], fontconfig >= 2.10.92, [
     CFLAGS="$CFLAGS $FONTCONFIG_CFLAGS"
@@ -165,8 +90,8 @@ PKG_CHECK_MODULES([FONTCONFIG], fontconfig >= 2.10.92, [
 	fontconfig=true
     ], [fontconfig=false])
 fi
-AM_CONDITIONAL([FONTCONFIG], [test x$fontconfig = xtrue])
 
+### Coretext
 if test x$enable_coretext != xno; then
 # Linking to CoreText directly only works from Mountain Lion and iOS.
 # In earlier OS X releases CoreText was part of the ApplicationServices
@@ -197,10 +122,8 @@ AC_COMPILE_IFELSE([
       ])
   ])
 fi
-AM_CONDITIONAL([CORETEXT], [test x$coretext = xtrue])
-
-
 
+### DirectWrite
 if test x$enable_directwrite != xno; then
 # Linking to DirectWrite directly only works from Windows
 AC_MSG_CHECKING([for DIRECTWRITE])
@@ -217,28 +140,20 @@ AC_LINK_IFELSE([
     AC_MSG_RESULT([no])
   ])
 fi
-AM_CONDITIONAL([DIRECTWRITE], [test x$directwrite = xtrue])
-
-PKG_CHECK_MODULES([HARFBUZZ], harfbuzz >= 1.2.3, [
-    CFLAGS="$CFLAGS $HARFBUZZ_CFLAGS"
-    LIBS="$LIBS $HARFBUZZ_LIBS"
-    AC_DEFINE(CONFIG_HARFBUZZ, 1, [found harfbuzz via pkg-config])
-    ])
 
-libpng=false
-if test x$enable_test = xyes || test x$enable_compare = xyes; then
-PKG_CHECK_MODULES([LIBPNG], libpng >= 1.2.0, [
-    CFLAGS="$CFLAGS $LIBPNG_CFLAGS"
-    AC_DEFINE(CONFIG_LIBPNG, 1, [found libpng via pkg-config])
-    libpng=true])
+## Require at least one system font provider by default
+if test x$enable_require_system_font_provider != xno &&
+   test x$fontconfig != xtrue &&
+   test x$directwrite != xtrue &&
+   test x$coretext != xtrue
+then
+    AC_MSG_ERROR([\
+Either DirectWrite (on Windows), CoreText (on OSX), or Fontconfig \
+(Linux, other) is required. If you really want to compile without \
+a system font provider, add --disable-require-system-font-provider])
 fi
 
-AM_CONDITIONAL([ENABLE_TEST], [test x$enable_test = xyes && test x$libpng = xtrue])
-AM_CONDITIONAL([ENABLE_COMPARE], [test x$enable_compare = xyes && test x$libpng = xtrue])
-
-AM_CONDITIONAL([ENABLE_PROFILE], [test x$enable_profile = xyes])
-
-# add packages to pkg-config for static linking
+## Now add packages to pkg-config for static linking
 if test "$use_libiconv" = true; then
     AC_DEFINE(CONFIG_ICONV, 1, [use iconv])
     if test x"$ac_cv_search_libiconv_open" != x"none required" &&
@@ -253,23 +168,121 @@ if test x$fontconfig = xtrue; then
     pkg_requires="fontconfig >= 2.10.92, ${pkg_requires}"
 fi
 
-if test x$enable_require_system_font_provider != xno &&
-   test x$fontconfig != xtrue &&
-   test x$directwrite != xtrue &&
-   test x$coretext != xtrue
-then
-    AC_MSG_ERROR([\
-Either DirectWrite (on Windows), CoreText (on OSX), or Fontconfig \
-(Linux, other) is required. If you really want to compile without \
-a system font provider, add --disable-require-system-font-provider])
-fi
 
+# Locate and configure Assembler appropriately
+AS_IF([test x$enable_asm != xno], [
+    AS_CASE([$host],
+        [i?86-*], [
+            INTEL=true
+            AS=nasm
+            X86=true
+            BITS=32
+            BITTYPE=32
+            ASFLAGS="$ASFLAGS -DARCH_X86_64=0" ],
+        [x86_64-*-gnux32|amd64-*-gnux32], [
+            AS=nasm
+            INTEL=true
+            X64=true
+            BITS=64
+            BITTYPE=x32
+            ASFLAGS="$ASFLAGS -DARCH_X86_64=1 -DPIC" ],
+        [x86_64-*|amd64-*], [
+            AS=nasm
+            INTEL=true
+            X64=true
+            BITS=64
+            BITTYPE=64
+            ASFLAGS="$ASFLAGS -DARCH_X86_64=1 -DPIC" ],
+        )
+    AS_IF([test x$INTEL = xtrue], [
+        AC_CHECK_PROG([nasm_check], [$AS], [yes])
+        AS_IF([test x$nasm_check != xyes], [
+            AC_MSG_WARN(nasm was not found; ASM functions are disabled.)
+            AC_MSG_WARN(Install nasm for a significantly faster libass build.)
+            enable_asm=no
+        ], [
+            AS_CASE([$host],
+                [*darwin*], [
+                    ASFLAGS="$ASFLAGS -f macho$BITTYPE -DPREFIX -DHAVE_ALIGNED_STACK=1" ],
+                [*linux*|*dragonfly*|*bsd*|*solaris*|*haiku*], [
+                    ASFLAGS="$ASFLAGS -f elf$BITTYPE -DHAVE_ALIGNED_STACK=1" ],
+                [*cygwin*|*mingw*], [
+                    ASFLAGS="$ASFLAGS -f win$BITTYPE"
+                    AS_IF([test x$BITS = x64], [
+                        ASFLAGS="$ASFLAGS -DHAVE_ALIGNED_STACK=1"
+                    ], [
+                        ASFLAGS="$ASFLAGS -DHAVE_ALIGNED_STACK=0 -DPREFIX"
+                    ])
+                ],
+                [ #default
+                    AC_MSG_ERROR(m4_text_wrap(m4_normalize([
+                            Please contact libass upstream to figure out if ASM
+                            support for your platform can be added.
+                            In the meantime you will need to use --disable-asm.]),
+                        [                  ],
+                        [could not identify NASM format for $host !],
+                        [78])
+                    )
+                ]
+            )
+            ASFLAGS="$ASFLAGS -DHAVE_CPUNOP=0 -Dprivate_prefix=ass"
+            AC_MSG_CHECKING([if $AS supports vpmovzxwd])
+            echo "vpmovzxwd ymm0, xmm0" > conftest.asm
+            AS_IF([$AS conftest.asm $ASFLAGS -o conftest.o >conftest.log 2>&1], [
+                AC_MSG_RESULT([yes])
+            ], [
+                AC_MSG_RESULT([no])
+                VER=`($AS --version || echo no assembler) 2>/dev/null | head -n 1`
+                AC_MSG_WARN([nasm is too old (found $VER); ASM functions are disabled.])
+                AC_MSG_WARN([Install nasm-2.10 or later for a significantly faster libass build.])
+                enable_asm=no
+            ])
+            rm conftest.asm conftest.o > /dev/null 2>&1
+        ])
+    ])
+])
+
+
+# Relay config results to output files
+
+## Tell Makefiles which assembler and flags to use
+AC_SUBST([ASFLAGS], ["$ASFLAGS"])
+AC_SUBST([AS], ["$AS"])
+
+## Relay package configuration to Makefiles
 AC_SUBST([PKG_LIBS_DEFAULT], [$(test x$enable_shared = xno && echo ${pkg_libs})])
 AC_SUBST([PKG_REQUIRES_DEFAULT], [$(test x$enable_shared = xno && echo ${pkg_requires})])
 AC_SUBST([PKG_LIBS_PRIVATE], [$(test x$enable_shared = xno || echo ${pkg_libs})])
 AC_SUBST([PKG_REQUIRES_PRIVATE], [$(test x$enable_shared = xno || echo ${pkg_requires})])
 
-# Setup output beautifier.
+## Setup conditionals for use in Makefiles
+AM_CONDITIONAL([ASM], [test x$enable_asm != xno])
+AM_CONDITIONAL([INTEL], [test x$INTEL = xtrue])
+AM_CONDITIONAL([X86], [test x$X86 = xtrue])
+AM_CONDITIONAL([X64], [test x$X64 = xtrue])
+
+AM_CONDITIONAL([ENABLE_LARGE_TILES], [test x$enable_large_tiles = xyes])
+
+AM_CONDITIONAL([ENABLE_COMPARE], [test x$enable_compare = xyes && test x$libpng = xtrue])
+AM_CONDITIONAL([ENABLE_TEST], [test x$enable_test = xyes && test x$libpng = xtrue])
+AM_CONDITIONAL([ENABLE_PROFILE], [test x$enable_profile = xyes])
+
+AM_CONDITIONAL([FONTCONFIG], [test x$fontconfig = xtrue])
+AM_CONDITIONAL([CORETEXT], [test x$coretext = xtrue])
+AM_CONDITIONAL([DIRECTWRITE], [test x$directwrite = xtrue])
+
+## Define C Macros not relating to libraries
+AM_COND_IF([ASM],
+    [AC_DEFINE(CONFIG_ASM, 1, [ASM enabled])],
+    [AC_DEFINE(CONFIG_ASM, 0, [ASM enabled])]
+    )
+
+AM_COND_IF([ENABLE_LARGE_TILES],
+    [AC_DEFINE(CONFIG_LARGE_TILES, 1, [use large tiles])]
+    [AC_DEFINE(CONFIG_LARGE_TILES, 0, [use small tiles])],
+    )
+
+## Setup output beautifier.
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
 AC_CONFIG_FILES([Makefile libass/Makefile test/Makefile compare/Makefile profile/Makefile libass.pc])