[epiphany] build: Get rid of some unused portability checks

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 9eb4e6d1c9f6a04ddb27d0ec725cd1c4b3f85045
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sat Nov 7 17:05:38 2015 -0600

    build: Get rid of some unused portability checks

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index abdce32..d135895 100644
--- a/configure.ac
+++ b/configure.ac
@@ -129,10 +129,10 @@ AC_SUBST([WEB_EXTENSION_LIBS])
 # Portability checks
 # ******************
 
-AC_CHECK_FUNCS([localtime_r memchr memmove memset mkdir mkdtemp realpath sqrt strchr strcspn strdup strerror 
strrchr strtol strtoul strstr])
+AC_CHECK_FUNCS([mkdtemp])
 
 # for backtrace()
-AC_CHECK_HEADERS([execinfo.h fcntl.h])
+AC_CHECK_HEADERS([execinfo.h])
 AC_SEARCH_LIBS([backtrace], [c execinfo])
 AC_C_INLINE
 AC_FUNC_MKTIME