build: try to make examples build both in-tree and out-of-tree

The examples simple.c and cocoabasic.m can be compiled without
installing libmpv. But also, they didn't use the correct include path
libmpv programs normally use, so they couldn't be built with a properly
installed system-libmpv. That's pretty bad for examples, which are
supposed to show how to use libmpv correctly.

So do some bullshit that symlinks libmpv to a "mpv" include directory
under the build directory. This name-mismatch is a direct consequence of
the bullshit done in 499a6758 (requested in #539 for dumb reasons). (We
don't want to name the client API headers directory "mpv", because that
would be too unspecific, and clashes with having the mpv binary in the
same directory.)

If you have spaces or other "unusual" characters in your paths, the
build will break, because I couldn't find out where waf hides its
function to escape shell parameters (or a way to invoke programs
without involving the shell). Neither does such a thing to be
documented, nor do they seem to have a clear way to do this in
their code.

This also doesn't compile the Qt examples, because everything becomes
even more terrible from there on.

4 files changed, 17 insertions, 4 deletions

diff --git a/DOCS/client_api_examples/cocoa/cocoabasic.m b/DOCS/client_api_examples/cocoa/cocoabasic.m
index 74f8f2e864..ea3e9c69d5 100644
--- a/DOCS/client_api_examples/cocoa/cocoabasic.m
+++ b/DOCS/client_api_examples/cocoa/cocoabasic.m
@@ -3,7 +3,7 @@
 // but that's not quite ready yet.
 // You may need a basic Info.plist and MainMenu.xib to make this work.
 
-#include "libmpv/client.h"
+#include <mpv/client.h>
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/DOCS/client_api_examples/simple/simple.c b/DOCS/client_api_examples/simple/simple.c
index 62fc9e8061..ca8699a076 100644
--- a/DOCS/client_api_examples/simple/simple.c
+++ b/DOCS/client_api_examples/simple/simple.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "libmpv/client.h"
+#include <mpv/client.h>
 
 static inline void check_error(int status)
 {
diff --git a/wscript b/wscript
index 338ded3638..98b8eab1ea 100644
--- a/wscript
+++ b/wscript
@@ -29,6 +29,8 @@ build_options = [
         'name': '--client-api-examples',
         'desc': 'build client API examples',
         'deps_any': [ 'libmpv-shared', 'libmpv-static' ],
+        # The build process uses symlinks (ln -s)
+        'deps_neg': [ 'os-win32' ],
         'func': check_true
     }, {
         'name': '--static-build',
diff --git a/wscript_build.py b/wscript_build.py
index 694a65b038..2771bbbbec 100644
--- a/wscript_build.py
+++ b/wscript_build.py
@@ -528,15 +528,26 @@ def build(ctx):
             ( "cocoa/cocoabasic.m", "cocoa" ),
         ]
 
+        # Create a "local" include dir, so we can build the examples without
+        # installing the headers.
+        incdir = os.path.join(ctx.bldnode.abspath(), "include")
+        ctx(
+            rule   = "mkdir -p {1} && ln -s {0} {1}/mpv".format(
+                        os.path.join(ctx.srcnode.abspath(), "libmpv"), incdir),
+            before = ("c",),
+            name = "incdir",
+        )
+
         for source in ctx.filtered_sources(examples_sources):
             ctx(
                 target       = os.path.splitext(source)[0],
                 source       = "DOCS/client_api_examples/" + source,
-                includes     = [ctx.bldnode.abspath(), ctx.srcnode.abspath()],
-                use          = "mpv",
+                includes     = [incdir, ctx.srcnode.abspath()],
+                use          = "mpv incdir",
                 features     = "c cprogram",
                 install_path = None
             )
+            ctx.env.CFLAGS += ['-isystem', incdir]
 
     if ctx.dependency_satisfied("vf-dlopen-filters"):
         dlfilters = "telecine tile rectangle framestep ildetect".split()