Add feature test macro _POSIX_C_SOURCE to enable fileno()

Flex prior to 2.6.6 uses fileno() but does not define the needed
feature test macros.
See westes/flex#263 for details.

Signed-off-by: Joseph Schuchart <[email protected]>

Author: devreal

opal/util/Makefile.am

@@ -138,6 +138,12 @@ libopalutil_core_la_DEPENDENCIES = \
         json/libopalutil_json.la \
         keyval/libopalutilkeyval.la
 
+# flex prior to version 2.6.6 uses the POSIX extension fileno()
+# without providing the proper feature test macro, so
+# we add the _POSIX_C_SOURCE macro here.
+# See https://github.com/westes/flex/issues/263
+libopalutil_core_la_CFLAGS = -D_POSIX_C_SOURCE=200809L
+
 # Conditionally install the header files
 
 if WANT_INSTALL_HEADERS

opal/util/keyval/Makefile.am

@@ -30,5 +30,11 @@ libopalutilkeyval_la_SOURCES = \
 	keyval_lex.h \
         keyval_lex.l
 
+# flex prior to version 2.6.6 uses the POSIX extension fileno()
+# without providing the proper feature test macro, so
+# we add the _POSIX_C_SOURCE macro here.
+# See https://github.com/westes/flex/issues/263
+libopalutilkeyval_la_CFLAGS = -D_POSIX_C_SOURCE=200809L
+
 maintainer-clean-local:
 	rm -f keyval_lex.c