CMake: use Requires: for .pc generation (don't parse link flags)

Instead of trying to translate/parse the INTERFACE link flags from CMake
to the .pc file, make use of the more native-to-pkg-config "Requires"
and "Requires.private", so that we can refer to the whole dependent .pc
pacakge name.

This fixes static linking when the dependencies of static libraries are
also static, and allows for using pkg-config all the way down.

When sasl and zlib are found, Rfb public headers also include headers
from these libraries so they are the only ones listed in "Requires".
The others can be in "Requires.private".

Signed-off-by: Johannes Kauffmann <johanneskauffmann@hotmail.com>

Author: JohannesKauffmann

CMakeLists.txt

@@ -247,13 +247,15 @@ if(SYSTEMD_FOUND)
   add_definitions(-DLIBVNCSERVER_WITH_SYSTEMD)
   include_directories(${SYSTEMD_INCLUDE_DIRS})
   set(ADDITIONAL_LIBS ${ADDITIONAL_LIBS} ${SYSTEMD_LIBRARIES})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE libsystemd)
 endif(SYSTEMD_FOUND)
 
 # common crypto used by both libvncserver and libvncclient
 if(WITH_GCRYPT AND LIBGCRYPT_LIBRARIES)
   message(STATUS "Building crypto with Libgcrypt")
   set(CRYPTO_LIBRARIES ${LIBGCRYPT_LIBRARIES})
   set(CRYPTO_SOURCES ${COMMON_DIR}/crypto_libgcrypt.c)
+  list(APPEND LIBVNC_REQUIRES_PRIVATE libgcrypt)
 elseif(OPENSSL_FOUND)
   message(STATUS "Building crypto with OpenSSL")
   set(CRYPTO_LIBRARIES ${OPENSSL_LIBRARIES})
@@ -344,6 +346,7 @@ if(WITH_SASL AND LIBSASL2_LIBRARIES AND SASL2_INCLUDE_DIR)
   set(LIBVNCSERVER_HAVE_SASL 1)
   set(ADDITIONAL_LIBS ${ADDITIONAL_LIBS} ${LIBSASL2_LIBRARIES})
   include_directories(${SASL2_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES sasl)
 endif(WITH_SASL AND LIBSASL2_LIBRARIES AND SASL2_INCLUDE_DIR)
 
 # TODO:
@@ -405,6 +408,7 @@ if(GNUTLS_FOUND)
     ${LIBVNCSERVER_DIR}/rfbssl_gnutls.c
     )
   include_directories(${GNUTLS_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE gnutls)
 elseif(OPENSSL_FOUND)
   message(STATUS "Building TLS with OpenSSL")
   set(LIBVNCCLIENT_SOURCES
@@ -416,6 +420,7 @@ elseif(OPENSSL_FOUND)
     ${LIBVNCSERVER_DIR}/rfbssl_openssl.c
   )
   include_directories(${OPENSSL_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE openssl)
 else()
   message(STATUS "Building without TLS")
   set(LIBVNCCLIENT_SOURCES
@@ -438,6 +443,7 @@ endif()
 if(ZLIB_FOUND)
   add_definitions(-DLIBVNCSERVER_HAVE_LIBZ)
   include_directories(${ZLIB_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES zlib)
   set(LIBVNCSERVER_SOURCES
     ${LIBVNCSERVER_SOURCES}
     ${LIBVNCSERVER_DIR}/zlib.c
@@ -450,6 +456,7 @@ endif(ZLIB_FOUND)
 if(LZO_FOUND)
   add_definitions(-DLIBVNCSERVER_HAVE_LZO)
   include_directories(${LZO_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE lzo2)
 else()
   set(LIBVNCSERVER_SOURCES
     ${LIBVNCSERVER_SOURCES}
@@ -464,6 +471,7 @@ endif()
 if(JPEG_FOUND)
   add_definitions(-DLIBVNCSERVER_HAVE_LIBJPEG)
   include_directories(${JPEG_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE libjpeg)
   if(PNG_FOUND OR ZLIB_FOUND)
     set(TIGHT_C ${LIBVNCSERVER_DIR}/tight.c ${COMMON_DIR}/turbojpeg.c)
   endif(PNG_FOUND OR ZLIB_FOUND)
@@ -472,6 +480,7 @@ endif(JPEG_FOUND)
 if(PNG_FOUND)
   add_definitions(-DLIBVNCSERVER_HAVE_LIBPNG)
   include_directories(${PNG_INCLUDE_DIR})
+  list(APPEND LIBVNC_REQUIRES_PRIVATE libpng)
 endif(PNG_FOUND)
 
 set(LIBVNCSERVER_SOURCES
@@ -763,37 +772,14 @@ endif(LIBVNCSERVER_WITH_WEBSOCKETS AND WITH_LIBVNCSERVER)
 
 endif(WITH_TESTS)
 
-#
-# this gets the libraries needed by TARGET in "-libx -liby ..." form
-#
-function(get_link_libraries OUT TARGET)
-    set(RESULT "")
-    get_target_property(LIBRARIES ${TARGET} INTERFACE_LINK_LIBRARIES)
-    foreach(LIB ${LIBRARIES})
-	if("${LIB}" MATCHES ".*NOTFOUND.*")
-	    continue()
-	endif()
-	string(REGEX REPLACE "^.*/lib" "" LIB ${LIB}) # remove leading path and "lib" name prefix
-	string(REGEX REPLACE "-l" "" LIB ${LIB}) # remove leading -l
-	string(REGEX REPLACE "\\.so$" "" LIB ${LIB}) # remove trailing .so
-	list(APPEND RESULT "-l${LIB}")
-    endforeach()
-    list(REMOVE_DUPLICATES RESULT)
-    string(CONCAT RESULT ${RESULT}) # back to string
-    if(RESULT)
-	string(REPLACE "-l" " -l" RESULT ${RESULT}) # re-add separators
-    endif(RESULT)
-    set(${OUT} ${RESULT} PARENT_SCOPE)
-endfunction()
-
+string(REPLACE ";" " " LIBVNC_REQUIRES "${LIBVNC_REQUIRES}")
+string(REPLACE ";" " " LIBVNC_REQUIRES_PRIVATE "${LIBVNC_REQUIRES_PRIVATE}")
 set(LIBVNCSERVER_PC_FILES )
 if(WITH_LIBVNCSERVER)
-  get_link_libraries(PRIVATE_LIBS vncserver)
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/src/libvncserver/libvncserver.pc.cmakein ${CMAKE_CURRENT_BINARY_DIR}/libvncserver.pc @ONLY)
   list(APPEND LIBVNCSERVER_PC_FILES ${CMAKE_CURRENT_BINARY_DIR}/libvncserver.pc)
 endif(WITH_LIBVNCSERVER)
 if(WITH_LIBVNCCLIENT)
-  get_link_libraries(PRIVATE_LIBS vncclient)
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/src/libvncclient/libvncclient.pc.cmakein ${CMAKE_CURRENT_BINARY_DIR}/libvncclient.pc @ONLY)
   list(APPEND LIBVNCSERVER_PC_FILES ${CMAKE_CURRENT_BINARY_DIR}/libvncclient.pc)
 endif(WITH_LIBVNCCLIENT)

src/libvncclient/libvncclient.pc.cmakein

@@ -6,9 +6,7 @@ includedir=@CMAKE_INSTALL_PREFIX@/include
 Name: LibVNCClient
 Description: A library for easy implementation of a VNC client.
 Version: @LibVNCServer_VERSION@
-Requires:
-Requires.private:
+Requires: @LIBVNC_REQUIRES@
+Requires.private: @LIBVNC_REQUIRES_PRIVATE@
 Libs: -L${libdir} -lvncclient
-Libs.private: @PRIVATE_LIBS@
 Cflags: -I${includedir}
-

src/libvncserver/libvncserver.pc.cmakein

@@ -6,8 +6,7 @@ includedir=@CMAKE_INSTALL_PREFIX@/include
 Name: LibVNCServer
 Description: A library for easy implementation of a VNC server.
 Version: @LibVNCServer_VERSION@
-Requires:
-Requires.private:
+Requires: @LIBVNC_REQUIRES@
+Requires.private: @LIBVNC_REQUIRES_PRIVATE@
 Libs: -L${libdir} -lvncserver
-Libs.private: @PRIVATE_LIBS@
 Cflags: -I${includedir}