Static lib handling for libevent

Summary: Add shared_libs=off conditional section to the libevent manifest to set EVENT__LIBRARY_TYPE=STATIC when building static libraries.

Reviewed By: bigfootjon

Differential Revision: D93644393

fbshipit-source-id: 90f1ec11981d5d2e1676847b0ff1e94e29bd092c

Author: afrind

build/fbcode_builder/manifests/libevent

@@ -34,6 +34,9 @@ EVENT__DISABLE_REGRESS = ON
 [cmake.defines.shared_libs=on]
 EVENT__BUILD_SHARED_LIBRARIES = ON
 
+[cmake.defines.shared_libs=off]
+EVENT__LIBRARY_TYPE = STATIC
+
 [cmake.defines.os=windows]
 EVENT__LIBRARY_TYPE = STATIC