Makefile: add section for SGI IRIX 6.5

Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Makefile

@@ -830,6 +830,19 @@ ifeq ($(uname_S),GNU)
 	NO_STRLCPY=YesPlease
 	NO_MKSTEMPS = YesPlease
 endif
+ifeq ($(uname_S),IRIX)
+	NO_SETENV = YesPlease
+	NO_UNSETENV = YesPlease
+	NO_STRCASESTR = YesPlease
+	NO_MEMMEM = YesPlease
+	NO_MKSTEMPS = YesPlease
+	NO_MKDTEMP = YesPlease
+	NO_MMAP = YesPlease
+	NO_EXTERNAL_GREP = UnfortunatelyYes
+	SNPRINTF_RETURNS_BOGUS = YesPlease
+	SHELL_PATH = /usr/gnu/bin/bash
+	NEEDS_LIBGEN = YesPlease
+endif
 ifeq ($(uname_S),IRIX64)
 	NO_IPV6=YesPlease
 	NO_SETENV=YesPlease