Improve accuracy of check for presence of deflateBound.

ZLIB_VERNUM isn't defined in some zlib versions, so this patch does a proper
linking test in autoconf to see whether deflateBound exists in zlib. Also,
setting NO_DEFLATE_BOUND will also work for folk not using autoconf.

Signed-off-by: David Symonds <dsymonds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -94,6 +94,8 @@ all::
 # Define OLD_ICONV if your library has an old iconv(), where the second
 # (input buffer pointer) parameter is declared with type (const char **).
 #
+# Define NO_DEFLATE_BOUND if your zlib does not have deflateBound.
+#
 # Define NO_R_TO_GCC_LINKER if your gcc does not like "-R/path/lib"
 # that tells runtime paths to dynamic libraries;
 # "-Wl,-rpath=/path/lib" is used instead.
@@ -637,6 +639,10 @@ ifdef OLD_ICONV
 	BASIC_CFLAGS += -DOLD_ICONV
 endif
 
+ifdef NO_DEFLATE_BOUND
+	BASIC_CFLAGS += -DNO_DEFLATE_BOUND
+endif
+
 ifdef PPC_SHA1
 	SHA1_HEADER = "ppc/sha1.h"
 	LIB_OBJS += ppc/sha1.o ppc/sha1ppc.o

cache.h

@@ -6,7 +6,7 @@
 #include SHA1_HEADER
 #include <zlib.h>
 
-#if ZLIB_VERNUM < 0x1200
+#if defined(NO_DEFLATE_BOUND) || ZLIB_VERNUM < 0x1200
 #define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
 #endif
 

config.mak.in

@@ -38,3 +38,4 @@ NO_STRCASESTR=@NO_STRCASESTR@
 NO_STRLCPY=@NO_STRLCPY@
 NO_SETENV=@NO_SETENV@
 NO_ICONV=@NO_ICONV@
+NO_DEFLATE_BOUND=@NO_DEFLATE_BOUND@

configure.ac

@@ -182,6 +182,26 @@ AC_SUBST(NEEDS_LIBICONV)
 AC_SUBST(NO_ICONV)
 test -n "$NEEDS_LIBICONV" && LIBS="$LIBS -liconv"
 #
+# Define NO_DEFLATE_BOUND if deflateBound is missing from zlib.
+AC_DEFUN([ZLIBTEST_SRC], [
+#include <zlib.h>
+
+int main(void)
+{
+	deflateBound(0, 0);
+	return 0;
+}
+])
+AC_MSG_CHECKING([for deflateBound in -lz])
+old_LIBS="$LIBS"
+LIBS="$LIBS -lz"
+AC_LINK_IFELSE(ZLIBTEST_SRC,
+	[AC_MSG_RESULT([yes])],
+	[AC_MSG_RESULT([no])
+	NO_DEFLATE_BOUND=yes])
+LIBS="$old_LIBS"
+AC_SUBST(NO_DEFLATE_BOUND)
+#
 # Define NEEDS_SOCKET if linking with libc is not enough (SunOS,
 # Patrick Mauritz).
 AC_CHECK_LIB([c], [socket],