st/egl: Fix build on FreeBSD.

There is no libdl on FreeBSD.  Based on patch from Thinker
<thinker@branda.to>, which is against 7.8.

This fixes fdo bug #29093.

configs/autoconf.in

@@ -34,6 +34,8 @@ LLVM_LIBS = @LLVM_LIBS@
 GLW_CFLAGS = @GLW_CFLAGS@
 GLUT_CFLAGS = @GLUT_CFLAGS@
 
+# dlopen
+DLOPEN_LIBS = @DLOPEN_LIBS@
 
 # Source selection
 MESA_ASM_SOURCES = @MESA_ASM_SOURCES@

configs/default

@@ -131,6 +131,8 @@ VG_LIB_DEPS    = $(EXTRA_LIB_PATH) -lpthread
 APP_LIB_DEPS = -lm
 X11_LIBS = -lX11
 
+DLOPEN_LIBS = -ldl
+
 # Installation directories (for make install)
 INSTALL_DIR = /usr/local
 INSTALL_LIB_DIR = $(INSTALL_DIR)/$(LIB_DIR)

configure.ac

@@ -410,6 +410,7 @@ 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_SUBST([DLOPEN_LIBS])
 
 dnl See if posix_memalign is available
 AC_CHECK_FUNC([posix_memalign], [DEFINES="$DEFINES -DHAVE_POSIX_MEMALIGN"])

src/gallium/targets/egl/Makefile

@@ -37,7 +37,7 @@ egl_CPPFLAGS := \
 	-I$(TOP)/src/gallium/state_trackers/egl \
 	-I$(TOP)/src/egl/main \
 	-DPIPE_PREFIX=\"$(PIPE_PREFIX)\" -DST_PREFIX=\"$(ST_PREFIX)\"
-egl_SYS := -lm -ldl -L$(TOP)/$(LIB_DIR) -lEGL
+egl_SYS := -lm $(DLOPEN_LIBS) -L$(TOP)/$(LIB_DIR) -lEGL
 egl_LIBS := $(TOP)/src/gallium/state_trackers/egl/libegl.a
 
 ifneq ($(findstring x11, $(EGL_PLATFORMS)),)