m4: Add gst-platform.m4 for platform specific checks and defines

These are currently copied from core but some/most of them are
useful for other modules too.

diff --git a/m4/gst-platform.m4 b/m4/gst-platform.m4
new file mode 100644 (file)
index 0000000..c427c4f
--- /dev/null
+++ b/m4/gst-platform.m4
@@ -0,0 +1,55 @@
+dnl AG_GST_PLATFORM
+dnl Check for platform specific features and define some variables
+dnl
+dnl GST_EXTRA_MODULE_SUFFIX: contains a platform specific
+dnl   extra module suffix additional to G_MODULE_SUFFIX
+dnl
+dnl HAVE_OSX: Defined if compiling for OS X
+dnl
+dnl GST_HAVE_UNSAFE_FORK: Defined if fork is unsafe (Windows)
+dnl
+dnl HAVE_WIN32: Defined if compiling on Win32
+dnl
+
+AC_DEFUN([AG_GST_PLATFORM],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  case $host_os in
+    rhapsody*)
+      AC_DEFINE_UNQUOTED(GST_EXTRA_MODULE_SUFFIX, [".dylib"], [Extra platform specific plugin suffix])
+      ;;
+    darwin*)
+      AC_DEFINE_UNQUOTED(GST_EXTRA_MODULE_SUFFIX, [".dylib"], [Extra platform specific plugin suffix])
+      AC_DEFINE_UNQUOTED(HAVE_OSX, 1, [Defined if compiling for OSX])
+      ;;
+    cygwin*)
+      AC_DEFINE_UNQUOTED(GST_HAVE_UNSAFE_FORK, 1, [Defined when registry scanning through fork is unsafe])
+      ;;
+    mingw* | msvc* | mks*)
+      dnl HAVE_WIN32 currently means "disable POSIXisms".
+      AC_DEFINE_UNQUOTED(HAVE_WIN32, 1, [Defined if compiling for Windows])
+
+      dnl define __MSVCRT_VERSION__ version if not set already by the
+      dnl compiler (ie. mostly for mingw). This is needed for things like
+      dnl __stat64 to be available. If set by the compiler, ensure it's
+      dnl new enough - we need at least WinXP SP2.
+      AC_TRY_COMPILE([ ], [ return __MSVCRT_VERSION__; ], [
+          AC_TRY_COMPILE([ ], [
+            #if __MSVCRT_VERSION__ < 0x0601
+            #error "MSVCRT too old"
+            #endif
+          ], [
+            AC_MSG_NOTICE([MSVCRT version looks ok])
+          ], [
+            AC_MSG_ERROR([MSVCRT version too old, need at least WinXP SP2])
+          ])
+      ], [
+        AC_MSG_NOTICE([Setting MSVCRT version to 0x0601])
+        AC_DEFINE_UNQUOTED(__MSVCRT_VERSION__, 0x0601, [We need at least WinXP SP2 for __stat64])
+      ])
+      ;;
+     *)
+      ;;
+  esac
+])