defs.mak.in: restore autoconf LIBS functionality

This is a standard autoconf variable, it was probably disabled due to
how the graphics/Makefile works and the more complex detection taking
place there.

Needed to use it to add -lpthread to some platforms (freebsd/openbsd)
to make it build out the box.

scripts/configure.in

@@ -1401,6 +1401,19 @@ if test $usingX11 ; then
      gr_libs="$gr_libs \${X11_LDFLAGS}"
 fi
 
+dnl We use GR_LIBS for graphics but some autoconf helpers might edit LIBS
+dnl remove "-lcairo" from LIBS if present in GR_LIBS
+for find in \
+  cairo X11 GL GLU fontconfig freetype
+do
+  if echo "$gr_libs" | grep -q -- "\-l${find}" ; then
+    dnl Not all sed support wildcard '\?'
+    LIBS=`echo "$LIBS" | sed -e "s/\-l${find} \?//" | tr -d '\n'`
+    LIBS=`echo "$LIBS" | sed -e "s/\-l${find} //" | tr -d '\n'`
+    LIBS=`echo "$LIBS" | sed -e "s/\-l${find}//" | tr -d '\n'`
+  fi
+done
+
 dnl ----------------------------------------------------------------
 dnl Define system-specific settings
 dnl ----------------------------------------------------------------

scripts/defs.mak.in

@@ -46,6 +46,7 @@ LD_EXTRA_LIBS	       = @ld_extra_libs@
 LD_SHARED	       = @ld_extra_objs@
 TOP_EXTRA_LIBS	       = @top_extra_libs@
 SUB_EXTRA_LIBS	       = @sub_extra_libs@
+LIBS		       = @LIBS@
 
 MODULES               += @modules@
 UNUSED_MODULES        += @unused@