test for the presence of pci_system_init_dev_mem() before calling it.

This avoids creating a dependency on -current libpciaccess for
BSD systems other than OpenBSD (which don't otherwise need it).
(cherry picked from commit db248ffb84)

configure.ac

@@ -1308,6 +1308,13 @@ if test "x$XORG" = xyes -o "x$XGL" = xyes; then
 	XORG_LIBS="$COMPOSITE_LIB $FIXES_LIB $XEXTXORG_LIB $GLX_LIBS $RENDER_LIB $RANDR_LIB $DAMAGE_LIB $MIEXT_DAMAGE_LIB $MIEXT_SHADOW_LIB $XI_LIB $XKB_LIB $XPSTUBS_LIB $SELINUX_LIB"
 
 	PKG_CHECK_MODULES([PCIACCESS], [pciaccess >= 0.8.0])
+	SAVE_LIBS=$LIBS
+	SAVE_CFLAGS=$CFLAGS
+	CFLAGS=$PCIACCESS_CFLAGS
+	LIBS=$PCIACCESS_LIBS
+	AC_CHECK_FUNCS([pci_system_init_dev_mem])
+	LIBS=$SAVE_LIBS
+	CFLAGS=$SAVE_CFLAGS
 	XORG_SYS_LIBS="$XORG_SYS_LIBS $PCIACCESS_LIBS $DLOPEN_LIBS $GLX_SYS_LIBS"
 	XORG_CFLAGS="$XORG_CFLAGS $PCIACCESS_CFLAGS"
 

hw/xfree86/os-support/bsd/i386_video.c

@@ -212,8 +212,10 @@ xf86OSInitVidMem(VidMemInfoPtr pVidMem)
 	pVidMem->mapMem = mapVidMem;
 	pVidMem->unmapMem = unmapVidMem;
 
+#if HAVE_PCI_SYSTEM_INIT_DEV_MEM
 	if (useDevMem)
 		pci_system_init_dev_mem(devMemFd);
+#endif
 
 #ifdef HAS_MTRR_SUPPORT
 	if (useDevMem) {

include/xorg-config.h.in

@@ -115,6 +115,9 @@
 /* Have execinfo.h */
 #undef HAVE_EXECINFO_H
 
+/* Have pci_system_init_dev_mem() */
+#undef HAVE_PCI_SYSTEM_INIT_DEV_MEM
+
 /* Path to text files containing PCI IDs */
 #undef PCI_TXT_IDS_PATH