Add option LIBRESSL_SKIP_INSTALL

Internally LIBRESSL_SKIP_INSTALL, if not set becomes ENABLE_LIBRESSL_INSTALL so this by default is enabled.  defining LIBRESSL_SKIP_INSTALL before hand will disable all install() rules.
This is useful if another project includes and links to this statically.
I chose to add a prefix to avoid potential name collision because the options are cached globally.

If the installation is skipped, maybe it should also disable building apps?  I didn't do that.

1 files changed, 6 insertions, 2 deletions

diff --git a/ssl/CMakeLists.txt b/ssl/CMakeLists.txt
index bc2fea4..0e1c326 100644
--- a/ssl/CMakeLists.txt
+++ b/ssl/CMakeLists.txt
@@ -60,8 +60,12 @@ if (BUILD_SHARED)
                 ARCHIVE_OUTPUT_NAME ssl${SSL_POSTFIX})
         set_target_properties(ssl-shared PROPERTIES VERSION ${SSL_VERSION}
                 SOVERSION ${SSL_MAJOR_VERSION})
-        install(TARGETS ssl ssl-shared DESTINATION lib)
+        if(ENABLE_LIBRESSL_INSTALL)
+                install(TARGETS ssl ssl-shared DESTINATION lib)
+        endif(ENABLE_LIBRESSL_INSTALL)
 else()
         add_library(ssl STATIC ${SSL_SRC})
-        install(TARGETS ssl DESTINATION lib)
+        if(ENABLE_LIBRESSL_INSTALL)
+                install(TARGETS ssl DESTINATION lib)
+        endif(ENABLE_LIBRESSL_INSTALL)
 endif()