diff --git a/Makefile b/Makefile
index a8554ae..7060309 100644
--- a/Makefile
+++ b/Makefile
@@ -37,7 +37,8 @@ CONFIG=	HAVE_<stdio.h>		\
 	HAVE_<iostream>		\
 	HAVE_clearenv		\
 	HAVE_libm		\
-	HAVE_liboony
+	HAVE_liboony		\
+	HAVE_sbrk
 
 # Define what to test
 TESTS=product count-characters
diff --git a/config.gnu.mk b/config.gnu.mk
index bfde89c..e976fa0 100644
--- a/config.gnu.mk
+++ b/config.gnu.mk
@@ -84,6 +84,9 @@ AS_DEPEND=      $(CC)  $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MP -MF $@ -MT $(@:.d=) $<
 #  Configuration checks
 #------------------------------------------------------------------------------
 
-CC_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define HAVE_$*_H' $$($(CC) $(CFLAGS) $(CFLAGS_CONFIG_$*) "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe && echo 1 || echo 0) | tr '[:lower:]' '[:upper:]' | sed -e 's|[^[:alnum:]]|_|g' -e 's|_DEFINE_\(.*\)_0|/* \#undef \1 */|g' -e 's|_DEFINE_\(.*\)_1|\#define \1 1|g' > "$@"
-CXX_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define HAVE_$*' $$($(CXX) $(CXXFLAGS) $(CXXFLAGS_CONFIG_$*) "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe && echo 1 || echo 0) | tr '[:lower:]' '[:upper:]' | sed -e 's|[^[:alnum:]]|_|g' -e 's|_DEFINE_\(.*\)_0|/* \#undef \1 */|g' -e 's|_DEFINE_\(.*\)_1|\#define \1 1|g' > "$@"
-LIB_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define HAVE_LIB$*' $$($(CC) $(CCFLAGS) $(CXXFLAGS_CONFIG_$*) -l$* "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe && echo 1 || echo 0) | tr '[:lower:]' '[:upper:]' | sed -e 's|[^[:alnum:]]|_|g' -e 's|_DEFINE_\(.*\)_0|/* \#undef \1 */|g' -e 's|_DEFINE_\(.*\)_1|\#define \1 1|g' > "$@"
+CONFIG_UPPER=$(shell echo -n "$*" | tr '[:lower:]' '[:upper:]' | tr -c '[:alnum:]' '_')
+CONFIG_FLAGS=$(shell grep '// [A-Z]*FLAGS=' "$<" | sed -e 's|// [A-Z]*FLAGS=||g')
+
+CC_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define' HAVE_$(CONFIG_UPPER)_H $(shell $(CC) $(CFLAGS) $(CFLAGS_CONFIG_$*) $(CONFIG_FLAGS) "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe > "$<".out 2>&1 && echo 1 || echo 0) | sed -e 's|\#define \(.*\) 0|/* \#undef \1 */|g' > "$@"
+CXX_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define' HAVE_$(CONFIG_UPPER) $(shell $(CXX) $(CXXFLAGS) $(CXXFLAGS_CONFIG_$*) $(CONFIG_FLAGS) "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe > "$<".out 2>&1 && echo 1 || echo 0) | sed -e 's|\#define \(.*\) 0|/* \#undef \1 */|g' > "$@"
+LIB_CONFIG=	mkdir -p "$$(dirname "$@")" ; echo '\#define HAVE_LIB'$(CONFIG_UPPER) $$($(CC) $(CCFLAGS) $(CFLAGS_CONFIG_$*) -l$* "$<" -o "$<".exe > "$<".err 2>&1 && "$<".exe && echo 1 || echo 0) | sed -e 's|\#define \(.*\) 0|/* \#undef \1 */|g' > "$@"
diff --git a/config.h b/config.h
index 85ff58a..8916b0d 100644
--- a/config.h
+++ b/config.h
@@ -7,3 +7,4 @@
 /* #undef HAVE_CLEARENV_H */
 #define HAVE_LIBM 1
 /* #undef HAVE_LIBOONY */
+#define HAVE_SBRK_H 1