Don't try to build OGLRender.cpp without GL headers, warn

about it instead.

desmume/configure.ac

@@ -67,8 +67,13 @@ else
 fi
 
 dnl - Check for the OpenGL includes
-AC_CHECK_HEADERS([GL/gl.h])
-AC_CHECK_HEADERS([GL/glu.h])
+AC_CHECK_HEADERS([GL/gl.h],
+		 [AC_CHECK_HEADERS([GL/glu.h], [have_gl_h=yes], [have_gl_h=no])],
+		 [have_gl_h=no])
+if test "have_gl_h" = "no" ; then
+	AC_MSG_WARN([Building without GL support because of missing headers.])
+fi
+AM_CONDITIONAL([HAVE_GL], [test "${have_gl_h}" = "yes"])
 
 dnl - if --enable-osmesa is used, check for it
 AC_ARG_ENABLE([osmesa],

desmume/src/Makefile.am

@@ -28,7 +28,7 @@ libdesmume_a_SOURCES = \
 	wifi.cpp wifi.h \
 	mic.h \
 	MMU.cpp MMU.h MMU_timing.h NDSSystem.cpp NDSSystem.h registers.h \
-	OGLRender.cpp OGLRender.h \
+	OGLRender.h \
 	ROMReader.cpp ROMReader.h \
 	render3D.cpp render3D.h \
 	rtc.cpp rtc.h \
@@ -56,6 +56,10 @@ libdesmume_a_SOURCES = \
 	version.cpp version.h \
 	desmume_config.cpp desmume_config.h
 
+if HAVE_GL
+libdesmume_a_SOURCES += OGLRender.cpp
+endif
+
 if HAVE_OPENAL
 libdesmume_a_SOURCES += mic_openal.cpp
 else