Index: /issm/trunk-jpl/m4/issm_options.m4
===================================================================
--- /issm/trunk-jpl/m4/issm_options.m4	(revision 25642)
+++ /issm/trunk-jpl/m4/issm_options.m4	(revision 25643)
@@ -192,13 +192,7 @@
 
 	AC_MSG_CHECKING([if this is a Mac build])
-	MAC_FMEMOPEN=0
 	case "${host_os}" in
 		*darwin*)
 			IS_MAC=yes
-			if [[ $(system_profiler SPSoftwareDataType | $(which grep) "System Version:" | sed -e "s/[[:space:]]*System Version: macOS //" | cut -d "." -f 2) -ge 13 ]]; then
-				MAC_FMEMOPEN=yes
-			else
-				MAC_FMEMOPEN=no
-			fi
 		;;
 		*)
@@ -207,6 +201,15 @@
 	esac
 	AM_CONDITIONAL([MAC], [test "${IS_MAC}" == "yes"])
-	AM_CONDITIONAL([MAC_FMEMOPEN], [test "${MAC_FMEMOPEN}" == "yes"])
 	AC_MSG_RESULT([${IS_MAC}])
+
+	if test "${IS_MAC}" == "yes"; then
+		AC_MSG_CHECKING([for fmemopen])
+		FMEMOPEN=no
+		if [[ $(system_profiler SPSoftwareDataType | $(which grep) "System Version:" | sed -e "s/[[:space:]]*System Version: macOS //" | cut -d "." -f 2) -ge 13 ]]; then
+			FMEMOPEN=yes
+		fi
+		AM_CONDITIONAL([HAS_FMEMOPEN], [test "${FMEMOPEN}" == "yes"])
+		AC_MSG_RESULT([${FMEMOPEN}])
+	fi
 
 	IS_WINDOWS=no
@@ -666,5 +669,5 @@
 		AC_MSG_RESULT(${DAKOTA_MINOR})
 		AC_DEFINE_UNQUOTED(_DAKOTA_MINOR_, $DAKOTA_MINOR, [Dakota minor version number])
-		AC_MSG_CHECKING(for dakota build version)
+		AC_MSG_CHECKING(for Dakota build version)
 		AC_MSG_RESULT(${DAKOTA_BUILD})
 		AC_DEFINE_UNQUOTED(_DAKOTA_BUILD_, $DAKOTA_BUILD, [Dakota build version number])
Index: /issm/trunk-jpl/src/c/Makefile.am
===================================================================
--- /issm/trunk-jpl/src/c/Makefile.am	(revision 25642)
+++ /issm/trunk-jpl/src/c/Makefile.am	(revision 25643)
@@ -25,5 +25,5 @@
 #GLIBC sources {{{
 if MAC
-if !MAC_FMEMOPEN
+if !HAS_FMEMOPEN
 issm_sources += \
 	./ext/fmemopen/fmemopen.c
Index: /issm/trunk-jpl/src/c/modules/QmuStatisticsx/QmuStatisticsx.h
===================================================================
--- /issm/trunk-jpl/src/c/modules/QmuStatisticsx/QmuStatisticsx.h	(revision 25642)
+++ /issm/trunk-jpl/src/c/modules/QmuStatisticsx/QmuStatisticsx.h	(revision 25643)
@@ -7,6 +7,7 @@
 #include "../../classes/classes.h"
 
-#if MAC && !MAC_FMEMOPEN
+#if MAC && !HAS_FMEMOPEN
 #include "../../ext/fmemopen/fmemopen.h"
+_error_("should have loaded fmemopen")
 #endif