diff -Naur gmp-6.2.1/Makefile.am gmpbuild/Makefile.am
--- gmp-6.2.1/Makefile.am	2020-11-15 02:45:09.000000000 +0800
+++ gmpbuild/Makefile.am	2021-01-09 22:56:14.571708858 +0800
@@ -112,7 +112,7 @@
 LIBGMPXX_LT_AGE      = 6
 
 
-SUBDIRS = tests mpn mpz mpq mpf printf scanf rand cxx demos tune doc
+SUBDIRS = tests mpn mpz mpq mpf printf scanf rand cxx demos tune
 
 EXTRA_DIST = configfsf.guess configfsf.sub .gdbinit INSTALL.autoconf \
 	     COPYING.LESSERv3 COPYINGv2 COPYINGv3
diff -Naur gmp-6.2.1/Makefile.in gmpbuild/Makefile.in
--- gmp-6.2.1/Makefile.in	2020-11-15 02:45:16.000000000 +0800
+++ gmpbuild/Makefile.in	2021-01-10 16:15:37.387670402 +0800
@@ -572,7 +572,7 @@
 LIBGMPXX_LT_CURRENT = 10
 LIBGMPXX_LT_REVISION = 1
 LIBGMPXX_LT_AGE = 6
-SUBDIRS = tests mpn mpz mpq mpf printf scanf rand cxx demos tune doc
+SUBDIRS = tests mpn mpz mpq mpf printf scanf rand cxx demos tune
 
 # Put asl.h here for now.
 
diff -Naur gmp-6.2.1/configure gmpbuild/configure
--- gmp-6.2.1/configure	2020-11-15 02:45:15.000000000 +0800
+++ gmpbuild/configure	2021-01-10 16:13:59.196004951 +0800
@@ -27985,7 +27985,7 @@
 # FIXME: Upcoming version of autoconf/automake may not like broken lines.
 #        Right now automake isn't accepting the new AC_CONFIG_FILES scheme.
 
-ac_config_files="$ac_config_files Makefile mpf/Makefile mpn/Makefile mpq/Makefile mpz/Makefile printf/Makefile scanf/Makefile rand/Makefile cxx/Makefile tests/Makefile tests/devel/Makefile tests/mpf/Makefile tests/mpn/Makefile tests/mpq/Makefile tests/mpz/Makefile tests/rand/Makefile tests/misc/Makefile tests/cxx/Makefile doc/Makefile tune/Makefile demos/Makefile demos/calc/Makefile demos/expr/Makefile gmp.h:gmp-h.in gmp.pc:gmp.pc.in gmpxx.pc:gmpxx.pc.in"
+ac_config_files="$ac_config_files Makefile mpf/Makefile mpn/Makefile mpq/Makefile mpz/Makefile printf/Makefile scanf/Makefile rand/Makefile cxx/Makefile tests/Makefile tests/devel/Makefile tests/mpf/Makefile tests/mpn/Makefile tests/mpq/Makefile tests/mpz/Makefile tests/rand/Makefile tests/misc/Makefile tests/cxx/Makefile tune/Makefile demos/Makefile demos/calc/Makefile demos/expr/Makefile gmp.h:gmp-h.in gmp.pc:gmp.pc.in gmpxx.pc:gmpxx.pc.in"
 
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
@@ -29129,7 +29129,6 @@
     "tests/rand/Makefile") CONFIG_FILES="$CONFIG_FILES tests/rand/Makefile" ;;
     "tests/misc/Makefile") CONFIG_FILES="$CONFIG_FILES tests/misc/Makefile" ;;
     "tests/cxx/Makefile") CONFIG_FILES="$CONFIG_FILES tests/cxx/Makefile" ;;
-    "doc/Makefile") CONFIG_FILES="$CONFIG_FILES doc/Makefile" ;;
     "tune/Makefile") CONFIG_FILES="$CONFIG_FILES tune/Makefile" ;;
     "demos/Makefile") CONFIG_FILES="$CONFIG_FILES demos/Makefile" ;;
     "demos/calc/Makefile") CONFIG_FILES="$CONFIG_FILES demos/calc/Makefile" ;;