_XGetRequest API was backported to libx11-1.4.4 in:
http://git.openembedded.org/openembedded-core/commit/?id=e08604800fe1cb8f240f53c147ceb4ee08a29b91

This breaks e.g. libsdl-image build with:
| /OE/shr-core/tmp-eglibc/sysroots/qemux86-64/usr/lib/libSDL.so: undefined reference to `_XGetRequest'

For details see: https://bugzilla.redhat.com/show_bug.cgi?id=782251

Upstream-Status: Accepted

@@ -, +, @@ 
 added.
 src/video/x11/SDL_x11dyn.c |   24 ++++++++++++++++++++++++
 src/video/x11/SDL_x11sym.h |    6 ++++++
 2 files changed, 30 insertions(+), 0 deletions(-)
--- a/src/video/x11/SDL_x11dyn.c	
+++ a/src/video/x11/SDL_x11dyn.c	
@@ -109,6 +109,21 @@ char *(*pXGetICValues)(XIC, ...) = NULL;
 #undef SDL_X11_SYM
 
 
+static void *SDL_XGetRequest_workaround(Display* dpy, CARD8 type, size_t len)
+{
+	xReq *req;
+	WORD64ALIGN
+	if (dpy->bufptr + len > dpy->bufmax)
+		_XFlush(dpy);
+	dpy->last_req = dpy->bufptr;
+	req = (xReq*)dpy->bufptr;
+	req->reqType = type;
+	req->length = len / 4;
+	dpy->bufptr += len;
+	dpy->request++;
+	return req;
+}
+
 static int x11_load_refcount = 0;
 
 void SDL_X11_UnloadSymbols(void)
@@ -168,6 +183,15 @@ int SDL_X11_LoadSymbols(void)
 		X11_GetSym("XGetICValues",&SDL_X11_HAVE_UTF8,(void **)&pXGetICValues);
 		#endif
 
+		/*
+		 * In case we're built with newer Xlib headers, we need to make sure
+		 *  that _XGetRequest() is available, even on older systems.
+		 *  Otherwise, various Xlib macros we use will call a NULL pointer.
+		 */
+		if (!SDL_X11_HAVE_XGETREQUEST) {
+			p_XGetRequest = SDL_XGetRequest_workaround;
+		}
+
 		if (SDL_X11_HAVE_BASEXLIB) {  /* all required symbols loaded. */
 			SDL_ClearError();
 		} else {
--- a/src/video/x11/SDL_x11sym.h	
+++ a/src/video/x11/SDL_x11sym.h	
@@ -170,6 +170,12 @@ SDL_X11_SYM(void,_XRead32,(Display *dpy,register long *data,long len),(dpy,data,
 #endif
 
 /*
+ * libX11 1.4.99.1 added _XGetRequest, and macros use it behind the scenes.
+ */
+SDL_X11_MODULE(XGETREQUEST)
+SDL_X11_SYM(void *,_XGetRequest,(Display* a,CARD8 b,size_t c),(a,b,c),return)
+
+/*
  * These only show up on some variants of Unix.
  */
 #if defined(__osf__)