patch-CMakeLists.txt

--- CMakeLists.txt.orig	2020-11-22 14:00:22 UTC
+++ CMakeLists.txt
@@ -183,6 +183,11 @@ option (APPLE_MULTIPLE_ARCHITECTURES
 # directory is present you get this behavior regardless.
 option (CONVERT_WARNINGS_TO_ERRORS "Convert warnings into errors?" OFF)
 
+# (12) Allow perl usage to be explicitly disabled. It might exist on the
+# system, but the user may not necessarily want it to be used for one reason
+# or another.
+option (GEOGRAPHICLIB_NO_PERL "Disable usage of pod2man and pod2html" OFF)
+
 set (LIBNAME Geographic)
 if (MSVC OR CMAKE_CONFIGURATION_TYPES)
   # For multi-config systems and for Visual Studio, the debug version of
@@ -434,7 +439,7 @@ endif ()
 # documentation files into the source tree.  Skip Apple here because
 # man/makeusage.sh uses "head --lines -4" to drop the last 4 lines of a
 # file and there's no simple equivalent for MacOSX
-if (NOT WIN32 AND NOT APPLE)
+if (NOT WIN32 AND NOT APPLE AND NOT GEOGRAPHICLIB_NO_PERL)
   find_program (HAVE_POD2MAN pod2man)
   find_program (HAVE_POD2HTML pod2html)
   find_program (HAVE_COL col)