add the git prefix to the long version output

Tested on MacOS, written and not tested for Linux, not attempted for Windows

include/global.h

@@ -386,6 +386,7 @@ struct nomakedefs_s {
     const char *copyright_banner_c;
     const char *git_sha;
     const char *git_branch;
+    const char *git_prefix;
     const char *version_string;
     const char *version_id;
     unsigned long version_number;

src/date.c

@@ -29,6 +29,7 @@ struct nomakedefs_s nomakedefs = {
     "Version 1.0, built Jul 28 13:18:57 1987.",
     (const char *) 0,   /* git_sha */
     (const char *) 0,   /* git_branch */
+    (const char *) 0,	/* git_prefix */
     "1.0.0-0",
     "NetHack Version 1.0.0-0 - last build Tue Jul 28 13:18:57 1987.",
     0x01010000UL,
@@ -125,6 +126,9 @@ populate_nomakedefs(struct version_info *version)
 #ifdef NETHACK_GIT_BRANCH
     nomakedefs.git_branch = dupstr(NETHACK_GIT_BRANCH);
 #endif
+#ifdef NETHACK_GIT_PREFIX
+    nomakedefs.git_prefix = dupstr(NETHACK_GIT_PREFIX);
+#endif
 
     nomakedefs_populated = 1;
     return;
@@ -161,6 +165,11 @@ free_nomakedefs(void)
         free((genericptr_t) nomakedefs.git_branch),
             nomakedefs.git_branch = 0;
 #endif
+#ifdef NETHACK_GIT_PREFIX
+    if (nomakedefs.git_prefix)
+        free((genericptr_t) nomakedefs.git_prefix),
+            nomakedefs.git_prefix = 0;
+#endif
 
     /* values are Null now; dynamic vs static doesn't really matter anymore */
     nomakedefs_populated = 0;

src/version.c

@@ -58,6 +58,10 @@ getversionstring(char *buf, size_t bufsz)
                      "%sbranch:%s",
                      c++ ? "," : "", nomakedefs.git_branch);
 #endif
+        if (nomakedefs.git_prefix)
+            Snprintf(eos(buf), (bufsz - strlen(buf)) - 1,
+                     "%sprefix:%s",
+                     c++ ? "," : "", nomakedefs.git_prefix);
         if (c)
             Snprintf(eos(buf), (bufsz - strlen(buf)) - 1,
                      "%s", ")");

sys/unix/Makefile.src

@@ -765,7 +765,7 @@ $(TARGETPFX)sfstruct.o: sfstruct.c $(HACK_H)
 #	date.c should be recompiled any time any of the source or include code
 #	is modified.
 $(TARGETPFX)date.o: date.c $(HACK_H) $(HACKCSRC)  $(HOBJ) $(TARGET_HACKLIB)
-	$(TARGET_CC) $(TARGET_CFLAGS) $(GITHASH) $(GITBRANCH) -c -o $@ date.c
+	$(TARGET_CC) $(TARGET_CFLAGS) $(GITHASH) $(GITBRANCH) $(GITPREFIX) -c -o $@ date.c
 
 #	date.h should be remade any time any of the source or include code
 #	is modified.  Unfortunately, this would make the contents of this

sys/unix/hints/linux.370

@@ -288,6 +288,7 @@ VARDATND += $(sort $(VARDATND0))
 
 GIT_HASH := $(shell echo `git rev-parse --verify HEAD` 2>&1)
 GIT_BRANCH := $(shell echo `git rev-parse --abbrev-ref HEAD` 2>&1)
+GIT_PREFIX := $(shell echo `git config nethack.substprefix` 2>&1)
 
 ifdef GIT_HASH
 GITHASH = -DNETHACK_GIT_SHA=\"$(GIT_HASH)\"
@@ -295,6 +296,9 @@ endif
 ifdef GIT_BRANCH
 GITBRANCH = -DNETHACK_GIT_BRANCH=\"$(GIT_BRANCH)\"
 endif
+ifdef GIT_PREFIX
+GITPREFIX = -DNETHACK_GIT_PREFIX=\"$(GIT_PREFIX)\"
+endif
 
 ifdef WANT_LIBNH
 CFLAGS += -DSHIM_GRAPHICS -DNOTTYGRAPHICS -DNOSHELL -DLIBNH -fpic

sys/unix/hints/macOS.370

@@ -285,6 +285,7 @@ VARDATND += $(sort $(VARDATND0))
 
 GIT_HASH := $(shell echo `git rev-parse --verify HEAD` 2>&1)
 GIT_BRANCH := $(shell echo `git rev-parse --abbrev-ref HEAD` 2>&1)
+GIT_PREFIX := $(shell echo `git config nethack.substprefix` 2>&1)
 
 ifdef GIT_HASH
 GITHASH = -DNETHACK_GIT_SHA=\"$(GIT_HASH)\"
@@ -292,6 +293,9 @@ endif
 ifdef GIT_BRANCH
 GITBRANCH = -DNETHACK_GIT_BRANCH=\"$(GIT_BRANCH)\"
 endif
+ifdef GIT_PREFIX
+GITPREFIX = -DNETHACK_GIT_PREFIX=\"$(GIT_PREFIX)\"
+endif
 
 ifdef WANT_LIBNH
 CFLAGS += -DSHIM_GRAPHICS -DNOTTYGRAPHICS -DNOSHELL -DLIBNH