configure: add makeinfo option

Rename makeinfo enabled variable to makeinfo_command. Do not put
makeinfo_command in HAVE_LIST, it is not used.

configure

@@ -415,6 +415,7 @@ Toolchain options:
   --pkg-config-flags=FLAGS pass additional flags to pkgconf []
   --ranlib=RANLIB          use ranlib RANLIB [$ranlib_default]
   --doxygen=DOXYGEN        use DOXYGEN to generate API doc [$doxygen_default]
+  --makeinfo=MAKEINFO      use MAKEINFO to generate documentation [$makeinfo_default]
   --host-cc=HOSTCC         use host C compiler HOSTCC
   --host-cflags=HCFLAGS    use HCFLAGS when compiling for host
   --host-cppflags=HCPPFLAGS use HCPPFLAGS when compiling for host
@@ -2716,7 +2717,6 @@ HAVE_LIST="
     gzip
     ioctl_posix
     libdrm_getfb2
-    makeinfo
     makeinfo_html
     opencl_d3d11
     opencl_drm_arm
@@ -2898,6 +2898,7 @@ CMDLINE_SET="
     cxx
     dep_cc
     doxygen
+    makeinfo
     env
     extra_version
     gas
@@ -4381,7 +4382,7 @@ podpages_deps="perl"
 manpages_deps="perl pod2man"
 htmlpages_deps="perl"
 htmlpages_deps_any="makeinfo_html texi2html"
-txtpages_deps="perl makeinfo"
+txtpages_deps="perl makeinfo_command"
 doc_deps_any="manpages htmlpages podpages txtpages"
 
 # default parameters
@@ -4405,6 +4406,7 @@ stdcxx_default="c++17"
 cxx_default="g++"
 host_cc_default="gcc"
 doxygen_default="doxygen"
+makeinfo_default="makeinfo"
 install="install"
 ln_s_default="ln -s -f"
 glslc_default="glslc"
@@ -5053,7 +5055,7 @@ if enabled cuda_nvcc; then
 fi
 
 set_default arch cc cxx doxygen pkg_config ranlib strip sysinclude \
-    target_exec x86asmexe glslc metalcc metallib stdc stdcxx
+    target_exec x86asmexe glslc metalcc metallib stdc stdcxx makeinfo
 enabled cross_compile || host_cc_default=$cc
 set_default host_cc
 
@@ -7622,10 +7624,16 @@ enabled schannel &&
 
 enabled schannel && check_cc dtls_protocol "windows.h security.h schnlsp.h" "int i = SECPKG_ATTR_DTLS_MTU;" -DSECURITY_WIN32
 
-makeinfo --version > /dev/null 2>&1 && enable makeinfo  || disable makeinfo
+$makeinfo --version > /dev/null 2>&1 && enable makeinfo_command || disable makeinfo_command
-enabled makeinfo \
+if enabled makeinfo_command; then
-    && [ 0$(makeinfo --version | grep "texinfo" | sed 's/.*texinfo[^0-9]*\([0-9]*\)\..*/\1/') -ge 5 ] \
+  [ 0$($makeinfo --version | grep "texinfo" | sed 's/.*texinfo[^0-9]*\([0-9]*\)\..*/\1/') -ge 5 ] \
     && enable makeinfo_html || disable makeinfo_html
+else
+  if test $makeinfo != $makeinfo_default ; then
+    warn "Specified makeinfo \"$makeinfo\" not found."
+  fi
+fi
+
 disabled makeinfo_html && texi2html --help 2> /dev/null | grep -q 'init-file' && enable texi2html || disable texi2html
 perl -v            > /dev/null 2>&1 && enable perl      || disable perl
 pod2man --help     > /dev/null 2>&1 && enable pod2man   || disable pod2man
@@ -8515,7 +8523,7 @@ echo "safe bitstream reader     ${safe_bitstream_reader-no}"
 echo "texi2html enabled         ${texi2html-no}"
 echo "perl enabled              ${perl-no}"
 echo "pod2man enabled           ${pod2man-no}"
-echo "makeinfo enabled          ${makeinfo-no}"
+echo "makeinfo enabled          ${makeinfo_command-no}"
 echo "makeinfo supports HTML    ${makeinfo_html-no}"
 echo "experimental features     ${unstable-no}"
 echo "xmllint enabled           ${xmllint-no}"
@@ -8664,6 +8672,7 @@ LD_PATH=$LD_PATH
 DLLTOOL=$dlltool
 WINDRES=$windres
 DOXYGEN=$doxygen
+MAKEINFO=$makeinfo
 LDFLAGS=$LDFLAGS
 LDEXEFLAGS=$LDEXEFLAGS
 LDSOFLAGS=$LDSOFLAGS

doc/Makefile

@@ -54,7 +54,7 @@ TEXIDEP = perl $(SRC_PATH)/doc/texidep.pl $(SRC_PATH) $< $@ >$(@:%=%.d)
 doc/%.txt: TAG = TXT
 doc/%.txt: doc/%.texi
 	$(Q)$(TEXIDEP)
-	$(M)makeinfo --force --no-headers -o $@ $< 2>/dev/null
+	$(M)$(MAKEINFO) --force --no-headers -o $@ $< 2>/dev/null
 
 GENTEXI  = format codec
 GENTEXI := $(GENTEXI:%=doc/avoptions_%.texi)
@@ -69,11 +69,11 @@ doc/%-all.html: TAG = HTML
 ifdef HAVE_MAKEINFO_HTML
 doc/%.html: doc/%.texi $(SRC_PATH)/doc/t2h.pm $(GENTEXI)
 	$(Q)$(TEXIDEP)
-	$(M)makeinfo --html -I doc --no-split -D config-not-all --init-file=$(SRC_PATH)/doc/t2h.pm --output $@ $<
+	$(M)$(MAKEINFO) --html -I doc --no-split -D config-not-all --init-file=$(SRC_PATH)/doc/t2h.pm --output $@ $<
 
 doc/%-all.html: doc/%.texi $(SRC_PATH)/doc/t2h.pm $(GENTEXI)
 	$(Q)$(TEXIDEP)
-	$(M)makeinfo --html -I doc --no-split -D config-all --init-file=$(SRC_PATH)/doc/t2h.pm --output $@ $<
+	$(M)$(MAKEINFO) --html -I doc --no-split -D config-all --init-file=$(SRC_PATH)/doc/t2h.pm --output $@ $<
 else
 doc/%.html: doc/%.texi $(SRC_PATH)/doc/t2h.init $(GENTEXI)
 	$(Q)$(TEXIDEP)