mesa/dlopen: use HAVE_DLOPEN instead of _GNU_SOURCE

Patches changes mesa to use 'HAVE_DLOPEN' defined by configure and Android.mk
instead of _GNU_SOURCE for detecting dlopen capability. This makes dlopen to
work also on Android where _GNU_SOURCE is not defined.

[mattst88] v2: HAVE_DLOPEN is sufficient for including dlfcn.h, remove
	       mingw/blrts checks around dlfcn.h inclusion.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>

Android.common.mk

@@ -47,7 +47,9 @@ LOCAL_CFLAGS += \
 ifeq ($(strip $(MESA_ENABLE_ASM)),true)
 ifeq ($(TARGET_ARCH),x86)
 LOCAL_CFLAGS += \
-	-DUSE_X86_ASM
+	-DUSE_X86_ASM \
+	-DHAVE_DLOPEN \
+
 endif
 endif
 

configure.ac

@@ -499,8 +499,9 @@ MESA_PIC_FLAGS
 
 dnl Check to see if dlopen is in default libraries (like Solaris, which
 dnl has it in libc), or if libdl is needed to get it.
-AC_CHECK_FUNC([dlopen], [],
-    [AC_CHECK_LIB([dl], [dlopen], [DLOPEN_LIBS="-ldl"])])
+AC_CHECK_FUNC([dlopen], [DEFINES="$DEFINES -DHAVE_DLOPEN"],
+    [AC_CHECK_LIB([dl], [dlopen],
+       [DEFINES="$DEFINES -DHAVE_DLOPEN"; DLOPEN_LIBS="-ldl"])])
 AC_SUBST([DLOPEN_LIBS])
 
 dnl See if posix_memalign is available

src/mesa/main/dlopen.c

@@ -31,7 +31,7 @@
 #include "compiler.h"
 #include "dlopen.h"
 
-#if defined(_GNU_SOURCE) && !defined(__MINGW32__) && !defined(__blrts)
+#if defined(HAVE_DLOPEN)
 #include <dlfcn.h>
 #endif
 #if defined(_WIN32)
@@ -48,7 +48,7 @@ _mesa_dlopen(const char *libname, int flags)
 {
 #if defined(__blrts)
    return NULL;
-#elif defined(_GNU_SOURCE)
+#elif defined(HAVE_DLOPEN)
    flags = RTLD_LAZY | RTLD_GLOBAL; /* Overriding flags at this time */
    return dlopen(libname, flags);
 #elif defined(__MINGW32__)
@@ -80,7 +80,7 @@ _mesa_dlsym(void *handle, const char *fname)
    strncpy(fname2 + 1, fname, 998);
    fname2[999] = 0;
    u.v = dlsym(handle, fname2);
-#elif defined(_GNU_SOURCE)
+#elif defined(HAVE_DLOPEN)
    u.v = dlsym(handle, fname);
 #elif defined(__MINGW32__)
    u.v = (void *) GetProcAddress(handle, fname);
@@ -99,7 +99,7 @@ _mesa_dlclose(void *handle)
 {
 #if defined(__blrts)
    (void) handle;
-#elif defined(_GNU_SOURCE)
+#elif defined(HAVE_DLOPEN)
    dlclose(handle);
 #elif defined(__MINGW32__)
    FreeLibrary(handle);