imlib2_load: Use clock_gettime() when available

configure.ac

@@ -129,6 +129,16 @@ AM_CONDITIONAL(BUILD_X11, test "x$have_x" = "xyes")
 AC_CHECK_LIB(dl, dlopen, DLOPEN_LIBS=-ldl)
 AC_SUBST(DLOPEN_LIBS)
 
+AC_CHECK_FUNCS([clock_gettime], [have_clock_gettime=yes],
+  [AC_CHECK_LIB([rt], [clock_gettime], [have_clock_gettime=-lrt],
+     [have_clock_gettime=no])])
+if test "x$have_clock_gettime" != xno; then
+  AC_DEFINE(USE_MONOTONIC_CLOCK, 1, [Use monotonic clock from clock_gettime()])
+  if test "x$have_clock_gettime" != xyes; then
+    AC_SUBST(CLOCK_LIBS, [$have_clock_gettime])
+  fi
+fi
+
 
 AC_MSG_CHECKING(whether to enable jpeg support)
 AC_ARG_WITH([jpeg],

src/bin/Makefile.am

@@ -19,7 +19,7 @@ imlib2_conv_SOURCES = imlib2_conv.c
 imlib2_conv_LDADD   = $(top_builddir)/src/lib/libImlib2.la
 
 imlib2_load_SOURCES = imlib2_load.c
-imlib2_load_LDADD   = $(top_builddir)/src/lib/libImlib2.la
+imlib2_load_LDADD   = $(top_builddir)/src/lib/libImlib2.la $(CLOCK_LIBS)
 
 imlib2_show_SOURCES = imlib2_show.c
 imlib2_show_LDADD   = $(top_builddir)/src/lib/libImlib2.la -lX11 -lm

src/bin/imlib2_load.c

@@ -4,7 +4,11 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#if USE_MONOTONIC_CLOCK
+#include <time.h>
+#else
 #include <sys/time.h>
+#endif
 
 #ifndef X_DISPLAY_MISSING
 #define X_DISPLAY_MISSING