diff --git a/ChangeLog b/ChangeLog
index 0eb4725..ba4d97b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -325,6 +325,10 @@ interface (it was OK with the native interface).
 continue to work, falling back to interpretation if anything goes wrong with 
 JIT.
 
+51. Applied patches from Christian Persch to configure.ac to make use of the 
+AC_USE_SYSTEM_EXTENSIONS macro and to test for functions used by the JIT 
+modules.
+
 
 Version 10.22 29-July-2016
 --------------------------
diff --git a/configure.ac b/configure.ac
index 7b62d7f..8e7d8ae 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,9 +29,6 @@ AM_INIT_AUTOMAKE([dist-bzip2 dist-zip])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 AC_CONFIG_HEADERS(src/config.h)
 
-# This is a new thing required to stop a warning from automake 1.12
-m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
-
 # This was added at the suggestion of libtoolize (03-Jan-10)
 AC_CONFIG_MACRO_DIR([m4])
 
@@ -47,6 +44,7 @@ remember_set_CFLAGS="$CFLAGS"
 
 AC_PROG_CC
 AM_PROG_CC_C_O
+AC_USE_SYSTEM_EXTENSIONS
 
 if test "x$remember_set_CFLAGS" = "x"
 then
@@ -59,6 +57,9 @@ then
   fi
 fi
 
+# This is a new thing required to stop a warning from automake 1.12
+m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
+
 # Check for a 64-bit integer type
 AC_TYPE_INT64_T
 
@@ -435,7 +436,7 @@ AC_TYPE_SIZE_T
 
 # Checks for library functions.
 
-AC_CHECK_FUNCS(bcopy memmove strerror)
+AC_CHECK_FUNCS(bcopy memmove strerror mkostemp secure_getenv)
 
 # Check for the availability of libz (aka zlib)
 
@@ -518,9 +519,6 @@ if test "$enable_pcre2test_libedit" = "yes"; then
   AC_CHECK_LIB([edit], [readline], [LIBEDIT="-ledit"])
 fi
 
-# This facilitates -ansi builds under Linux
-dnl AC_DEFINE([_GNU_SOURCE], [], [Enable GNU extensions in glibc])
-
 PCRE2_STATIC_CFLAG=""
 if test "x$enable_shared" = "xno" ; then
   AC_DEFINE([PCRE2_STATIC], [1], [
diff --git a/src/config.h.in b/src/config.h.in
index 25c38bf..e04b209 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -78,6 +78,9 @@ sure both macros are undefined; an emulation function will then be used. */
 /* Define to 1 if you have the <memory.h> header file. */
 #undef HAVE_MEMORY_H
 
+/* Define to 1 if you have the `mkostemp' function. */
+#undef HAVE_MKOSTEMP
+
 /* Define if you have POSIX threads libraries and header files. */
 #undef HAVE_PTHREAD
 
@@ -90,6 +93,9 @@ sure both macros are undefined; an emulation function will then be used. */
 /* Define to 1 if you have the <readline/readline.h> header file. */
 #undef HAVE_READLINE_READLINE_H
 
+/* Define to 1 if you have the `secure_getenv' function. */
+#undef HAVE_SECURE_GETENV
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
@@ -297,9 +303,41 @@ sure both macros are undefined; an emulation function will then be used. */
 /* Define to any value for valgrind support to find invalid memory reads. */
 #undef SUPPORT_VALGRIND
 
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable threading extensions on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+
+
 /* Version number of package */
 #undef VERSION
 
+/* Define to 1 if on MINIX. */
+#undef _MINIX
+
+/* Define to 2 if the system does not provide POSIX.1 features except with
+   this defined. */
+#undef _POSIX_1_SOURCE
+
+/* Define to 1 if you need to in order for `stat' and other things to work. */
+#undef _POSIX_SOURCE
+
 /* Define to empty if `const' does not conform to ANSI C. */
 #undef const