[cmake] static build: populate private

in pkg-config files only add Requires.private and Libs.private if we
build a static library.

rdtk/templates/CMakeLists.txt

@@ -35,6 +35,11 @@ cleaning_configure_file(
 cleaning_configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/../include/rdtk/config.h)
 
 if(NOT RDTK_FORCE_STATIC_BUILD)
+  # Do not set Requires.Private if not a static build
+  if(NOT BUILD_SHARED_LIBS)
+    set(RDTK_PC_REQUIRES_PRIVATE "winpr${WINPR_VERSION_MAJOR} libssl")
+    set(RDTK_PC_LIBRARY_PRIVATE "")
+  endif()
   cleaning_configure_file(
     ${CMAKE_CURRENT_SOURCE_DIR}/rdtk.pc.in ${CMAKE_CURRENT_BINARY_DIR}/rdtk${RDTK_VERSION_MAJOR}.pc @ONLY
   )

rdtk/templates/rdtk.pc.in

@@ -9,7 +9,7 @@ Description: rdtk:
 URL: http://www.freerdp.com/
 Version: @RDTK_VERSION@
 Requires:
-Requires.private: winpr@WINPR_VERSION_MAJOR@
+Requires.private: @RDTK_PC_REQUIRES_PRIVATE@
 Libs: -L${libdir} ${libs}
-Libs.private: 
+Libs.private: @RDTK_PC_LIBRARY_PRIVATE@
 Cflags: -I${includedir}