Ecore: detect ieeefp.h existence instead of including it with compiler's macro

On Solaris, this header is necessary for finite(). Instead of including it
if the sun compiler is used, include it if it exists. This fixes a warning
if gcc is used on Solaris

configure.ac

@@ -1750,6 +1750,7 @@ sys/prctl.h \
 sys/resource.h \
 sys/timerfd.h \
 sys/un.h \
+ieeefp.h \
 ],[],[],
 [
  #ifdef HAVE_SYS_SOCKET_H

src/lib/ecore/ecore_main.c

@@ -11,13 +11,9 @@
 # endif
 #endif
 
-#ifdef __SUNPRO_C
-# include <ieeefp.h>
-# include <string.h>
-#endif
-
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 #include <math.h>
 #include <sys/types.h>
@@ -29,6 +25,10 @@
 # include <systemd/sd-daemon.h>
 #endif
 
+#ifdef HAVE_IEEEFP_H
+# include <ieeefp.h> /* for Solaris */
+#endif
+
 #ifdef _MSC_VER
 # include <float.h>
 #endif

src/lib/ecore/ecore_pipe.c

@@ -7,8 +7,8 @@
 #include <errno.h>
 #include <math.h>
 
-#ifdef __SUNPRO_C
-# include <ieeefp.h>
+#ifdef HAVE_IEEEFP_H
+# include <ieeefp.h> /* for Solaris */
 #endif
 
 #ifdef HAVE_ISFINITE