Support builds when sys/param.h is missing

An option is added to the Makefile to skip the inclusion of sys/param.h.
The only known platform with this condition thus far is the z/OS UNIX System
Services environment.

Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -165,6 +165,8 @@ all::
 # Define NO_POLL if you do not have or don't want to use poll().
 # This also implies NO_SYS_POLL_H.
 #
+# Define NO_SYS_PARAM_H if you don't have sys/param.h.
+#
 # Define NO_PTHREADS if you do not have or do not want to use Pthreads.
 #
 # Define NO_PREAD if you have a problem with pread() system call (e.g.
@@ -1739,6 +1741,9 @@ endif
 ifdef NO_SYS_POLL_H
 	BASIC_CFLAGS += -DNO_SYS_POLL_H
 endif
+ifdef NO_SYS_PARAM_H
+	BASIC_CFLAGS += -DNO_SYS_PARAM_H
+endif
 ifdef NO_INTTYPES_H
 	BASIC_CFLAGS += -DNO_INTTYPES_H
 endif

configure.ac

@@ -699,6 +699,12 @@ AC_CHECK_HEADER([sys/poll.h],
 [NO_SYS_POLL_H=UnfortunatelyYes])
 GIT_CONF_SUBST([NO_SYS_POLL_H])
 #
+# Define NO_SYS_PARAM_H if you don't have sys/param.h
+AC_CHECK_HEADER([sys/param.h],
+[NO_SYS_PARAM_H=],
+[NO_SYS_PARAM_H=UnfortunatelyYes])
+GIT_CONF_SUBST([NO_SYS_PARAM_H])
+#
 # Define NO_INTTYPES_H if you don't have inttypes.h
 AC_CHECK_HEADER([inttypes.h],
 [NO_INTTYPES_H=],

git-compat-util.h

@@ -104,7 +104,9 @@
 #endif
 #include <errno.h>
 #include <limits.h>
+#ifndef NO_SYS_PARAM_H
 #include <sys/param.h>
+#endif
 #include <sys/types.h>
 #include <dirent.h>
 #include <sys/time.h>