add LDFLAGS to statically link libvterm

libvterm defaults to generate a dynamic library, however the emacs
module prefers a static one.

Fix #333

Author: xofyarg

CMakeLists.txt

@@ -75,7 +75,7 @@ else()
     GIT_REPOSITORY https://github.com/Sbozzolo/libvterm-mirror.git
     GIT_TAG 64f1775952dbe001e989f2ab679563b54f2fca55
     CONFIGURE_COMMAND ""
-    BUILD_COMMAND ${LIBVTERM_BUILD_COMMAND} "CFLAGS='-fPIC'"
+    BUILD_COMMAND ${LIBVTERM_BUILD_COMMAND} "CFLAGS='-fPIC'" "LDFLAGS='-static'"
     BUILD_IN_SOURCE ON
     INSTALL_COMMAND "")