Fix man page building to not absolutely require xsltproc when using CMake.

This now handles the case where we are building from the released tar, or
building from git if xsltproc is available, or building from git if xsltproc
is not available.

ChangeLog.txt

@@ -1,6 +1,12 @@
 Broker:
 - Fix exporting of executable symbols on BSD when building via makefile.
 
+Build:
+- Fix man page building to not absolutely require xsltproc when using CMake.
+  This now handles the case where we are building from the released tar, or
+  building from git if xsltproc is available, or building from git if xsltproc
+  is not available.
+
 
 2.0.6 - 2021-01-28
 ==================

man/CMakeLists.txt

@@ -1,9 +1,12 @@
-if(NOT WIN32)
+# If we are building from a release tarball, the man pages should already be built, so them.
-	find_program(XSLTPROC xsltproc REQUIRED)
+# If we are building from git, then the man pages will not be built. In this
-	if(NOT XSLTPROC)
+# case, attempt to find xsltproc, and if found build the man pages. If xsltproc
-		message(FATAL_ERROR "xsltproc not found: manpages cannot be built")
+# could not be found, then the man pages will not be built or installed -
-	endif()
+# because the install is optional.
 
+if(NOT WIN32)
+	find_program(XSLTPROC xsltproc OPTIONAL)
+	if(XSLTPROC)
 		function(compile_manpage page)
 			add_custom_command(OUTPUT ${CMAKE_SOURCE_DIR}/man/${page}
 				COMMAND xsltproc ${CMAKE_SOURCE_DIR}/man/${page}.xml -o ${CMAKE_SOURCE_DIR}/man/
@@ -22,10 +25,23 @@ if(NOT WIN32)
 		compile_manpage("mosquitto-tls.7")
 		compile_manpage("mqtt.7")
 		compile_manpage("mosquitto.8")
+	else()
+		message(FATAL_ERROR "xsltproc not found: manpages cannot be built")
+	endif()
+
 endif()
 
-install(FILES mosquitto_ctrl.1 mosquitto_ctrl_dynsec.1 mosquitto_passwd.1 mosquitto_pub.1 mosquitto_sub.1 mosquitto_rr.1 DESTINATION ${CMAKE_INSTALL_MANDIR}/man1)
+install(FILES
-install(FILES libmosquitto.3 DESTINATION ${CMAKE_INSTALL_MANDIR}/man3)
+	mosquitto_ctrl.1
-install(FILES mosquitto.conf.5 DESTINATION ${CMAKE_INSTALL_MANDIR}/man5)
+	mosquitto_ctrl_dynsec.1
-install(FILES mosquitto-tls.7 mqtt.7 DESTINATION ${CMAKE_INSTALL_MANDIR}/man7)
+	mosquitto_passwd.1
-install(FILES mosquitto.8 DESTINATION ${CMAKE_INSTALL_MANDIR}/man8)
+	mosquitto_pub.1
+	mosquitto_sub.1
+	mosquitto_rr.1
+	DESTINATION ${CMAKE_INSTALL_MANDIR}/man1
+	OPTIONAL)
+
+install(FILES libmosquitto.3 DESTINATION ${CMAKE_INSTALL_MANDIR}/man3 OPTIONAL)
+install(FILES mosquitto.conf.5 DESTINATION ${CMAKE_INSTALL_MANDIR}/man5 OPTIONAL)
+install(FILES mosquitto-tls.7 mqtt.7 DESTINATION ${CMAKE_INSTALL_MANDIR}/man7 OPTIONAL)
+install(FILES mosquitto.8 DESTINATION ${CMAKE_INSTALL_MANDIR}/man8 OPTIONAL)