mandoc upstream does not support zstd compression.  However, Guix uses zstd
compression for its man pages, therefore — without support for this
compression method — mandoc would be quite useless.  Hence, this patchset uses
zlibWrapper from the zstd project to add zstd compression support to mandoc.

Upstream-status: https://inbox.vuxu.org/mandoc-discuss/Z5i0H+XrKVrZqAXB@asta-kit.de/T/#t

diff -upr mandoc-1.14.6.orig/Makefile mandoc-1.14.6/Makefile
--- mandoc-1.14.6.orig/Makefile	2025-01-11 16:20:31.511129163 +0100
+++ mandoc-1.14.6/Makefile	2025-01-11 19:16:35.924788821 +0100
@@ -251,7 +251,12 @@ LIBMANDOC_OBJS	 = $(LIBMAN_OBJS) \
 		   msec.o \
 		   preconv.o \
 		   read.o \
-		   tag.o
+		   tag.o \
+		   zstd_zlibwrapper.o \
+		   gzclose.o \
+		   gzlib.o \
+		   gzread.o \
+		   gzwrite.o
 
 ALL_COBJS	 = compat_err.o \
 		   compat_fts.o \
Only in mandoc-1.14.6: Makefile.orig
diff -upr mandoc-1.14.6.orig/configure mandoc-1.14.6/configure
--- mandoc-1.14.6.orig/configure	2025-01-11 16:20:31.511129163 +0100
+++ mandoc-1.14.6/configure	2025-01-11 19:16:35.924788821 +0100
@@ -430,7 +430,7 @@ fi
 [ "${FATAL}" -eq 0 ] || exit 1
 
 # --- LDADD ---
-LDADD="${LDADD} ${LD_NANOSLEEP} ${LD_RECVMSG} ${LD_OHASH} -lz"
+LDADD="${LDADD} ${LD_NANOSLEEP} ${LD_RECVMSG} ${LD_OHASH} -lz -lzstd"
 echo "selected LDADD=\"${LDADD}\"" 1>&2
 echo "selected LDADD=\"${LDADD}\"" 1>&3
 echo 1>&3
Only in mandoc-1.14.6: configure.orig
diff -upr mandoc-1.14.6.orig/read.c mandoc-1.14.6/read.c
--- mandoc-1.14.6.orig/read.c	2025-01-11 16:35:03.825441715 +0100
+++ mandoc-1.14.6/read.c	2025-01-11 19:16:35.924788821 +0100
@@ -37,7 +37,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <zlib.h>
+#include <zstd_zlibwrapper.h>
 
 #include "mandoc_aux.h"
 #include "mandoc.h"
@@ -627,7 +627,7 @@ mparse_open(struct mparse *curp, const char *file)
 	int		  fd, save_errno;
 
 	cp = strrchr(file, '.');
-	curp->gzip = (cp != NULL && ! strcmp(cp + 1, "gz"));
+	curp->gzip = (cp != NULL && (! strcmp(cp + 1, "gz") || ! strcmp(cp + 1, "zst")));
 
 	/* First try to use the filename as it is. */
 
Only in mandoc-1.14.6: read.c.orig