Declare all bundled libs as static

Otherwise it can happen that these are built as shared depending on the
options passed to CMake, which obviously isn't intended.

lib/bitop/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_library(bitop bit.c)
+add_library(bitop STATIC bit.c)
 target_link_libraries(bitop)
 
 include_directories(${LUA_INCLUDE_DIR})

lib/gmp/CMakeLists.txt

@@ -1,3 +1,3 @@
-add_library(gmp mini-gmp.c)
+add_library(gmp STATIC mini-gmp.c)
 target_link_libraries(gmp)
 

lib/jsoncpp/CMakeLists.txt

@@ -1,3 +1,3 @@
-add_library(jsoncpp jsoncpp.cpp)
+add_library(jsoncpp STATIC jsoncpp.cpp)
 target_link_libraries(jsoncpp)