add alloca test

GNUmakefile

@@ -225,6 +225,12 @@ havesigio.h: trysigio.c
 	if $(DIET) $(CC) $(CFLAGS) -c trysigio.c >/dev/null 2>&1; then echo "#define HAVE_SIGIO"; fi > $@
 	-rm -f trysigio.o
 
+havealloca.h: tryalloca.c
+	-rm -f $@
+	echo "#include <stdlib.h>" > $@
+	if $(DIET) $(CC) $(CFLAGS) -c tryalloca.c >/dev/null 2>&1; then echo "#include <alloca.h>"; fi >> $@
+	-rm -f tryalloca.o
+
 iopause.h: iopause.h1 iopause.h2 trypoll.c
 	-rm -f $@
 	if $(DIET) $(CC) $(CFLAGS) -o t trypoll.c >/dev/null 2>&1; then cp iopause.h2 iopause.h; else cp iopause.h1 iopause.h; fi

Makefile

@@ -585,7 +585,7 @@ uninstall:
 	rm -f $(patsubst %.3,$(MAN3DIR)/%.3,$(notdir $(wildcard */*.3)))
 	rm -f $(LIBDIR)/libowfat.a
 
-VERSION=libowfat-0.19
+VERSION=libowfat-0.20
 CURNAME=libowfat-0.19
 
 tar: clean rename
@@ -654,6 +654,12 @@ havesigio.h: trysigio.c
 	if $(DIET) $(CC) $(CFLAGS) -c trysigio.c >/dev/null 2>&1; then echo "#define HAVE_SIGIO"; fi > $@
 	-rm -f trysigio.o
 
+havealloca.h: tryalloca.c
+	-rm -f $@
+	echo "#include <stdlib.h>" > $@
+	if $(DIET) $(CC) $(CFLAGS) -c tryalloca.c >/dev/null 2>&1; then echo "#include <alloca.h>"; fi >> $@
+	-rm -f tryalloca.o
+
 iopause.h: iopause.h1 iopause.h2 trypoll.c
 	-rm -f $@
 	if $(DIET) $(CC) $(CFLAGS) -o t trypoll.c >/dev/null 2>&1; then cp iopause.h2 iopause.h; else cp iopause.h1 iopause.h; fi

havealloca.h

@@ -1,3 +1,2 @@
-#if defined(__linux__) || defined(_SGI_SOURCE) || defined(__hpux__) || defined(__sun__)
+#include <stdlib.h>
 #include <alloca.h>
-#endif

tryalloca.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+#include <alloca.h>
+
+main() {
+  char* c=alloca(23);
+}