cmake: Fix pkgconfig generation

Existing code didn't check for possible "empty" linked libraries
(e.g. Threads::Threads when compiler has built-in pthreads support).
Also adds support for compile options defined on linked dependencies.

cmake/Modules/ObsHelpers_Linux.cmake

@@ -25,21 +25,30 @@ function(export_target_pkgconf target)
   get_target_property(_TARGET_DEPENDENCIES ${target} INTERFACE_LINK_LIBRARIES)
   get_target_property(_TARGET_DEFINITIONS ${target}
                       INTERFACE_COMPILE_DEFINITIONS)
-  get_target_property(_TARGET_OPTIONS ${target} INTERFACE_LINK_OPTIONS)
+  get_target_property(_TARGET_OPTIONS ${target} INTERFACE_COMPILE_OPTIONS)
 
   foreach(_LIBRARY IN LISTS _TARGET_DEPENDENCIES)
     get_target_property(_LINK_LIBRARY ${_LIBRARY} INTERFACE_LINK_LIBRARIES)
     get_target_property(_LINK_DEFINITIONS ${_LIBRARY}
                         INTERFACE_COMPILE_DEFINITIONS)
-    list(APPEND _LINKED_LIBRARIES "${_LINK_LIBRARY}")
+    get_target_property(_LINK_OPTIONS ${_LIBRARY} INTERFACE_COMPILE_OPTIONS)
+
+    if(NOT "${_LINK_LIBRARY}" STREQUAL "_LINK_LIBRARY-NOTFOUND")
+      list(APPEND _LINKED_LIBRARIES "${_LINK_LIBRARY}")
+    endif()
 
     if(NOT "${_LINK_DEFINITIONS}" STREQUAL "_LINK_DEFINITIONS-NOTFOUND")
       list(APPEND _LINKED_DEFINITIONS "${_LINK_DEFINITIONS}")
     endif()
+
+    if(NOT "${_LINK_OPTIONS}" STREQUAL "_LINK_OPTIONS-NOTFOUND")
+      list(APPEND _LINKED_OPTIONS "${_LINK_OPTIONS}")
+    endif()
   endforeach()
 
   string(REPLACE ";" " " _LINKED_LIBRARIES "${_LINKED_LIBRARIES}")
   string(REPLACE ";" " " _LINKED_DEFINITIONS "${_LINKED_DEFINITIONS}")
+  string(REPLACE ";" " " _LINKED_OPTIONS "${_LINKED_OPTIONS}")
 
   if(NOT "${_TARGET_DEFINITIONS}" STREQUAL "_TARGET_DEFINITIONS-NOTFOUND")
     list(JOIN _TARGET_DEFINITIONS "-D" _TARGET_DEFINITIONS)
@@ -49,8 +58,7 @@ function(export_target_pkgconf target)
   endif()
 
   if(NOT "${_TARGET_OPTIONS}" STREQUAL "_TARGET_OPTIONS-NOTFOUND")
-    list(JOIN _TARGET_OPTIONS "-" _TARGET_OPTIONS)
-    set(_TARGET_OPTIONS "-${_TARGET_OPTIONS}")
+    list(JOIN _TARGET_OPTIONS " " _TARGET_OPTIONS)
   else()
     set(_TARGET_OPTIONS "")
   endif()

libobs/pkgconfig/libobs.pc.in

@@ -6,5 +6,5 @@ includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@/obs
 Name: libobs
 Description: OBS Studio Library
 Version: @OBS_VERSION_CANONICAL@
-Cflags: -I${includedir} @_TARGET_DEFINITIONS@ @_TARGET_OPTIONS@ @_LINKED_DEFINITIONS@
-Libs: -L${libdir} @_LINKED_LIBRARIES@
+Cflags: -I${includedir} @_TARGET_DEFINITIONS@ @_TARGET_OPTIONS@ @_LINKED_DEFINITIONS@ @_LINKED_OPTIONS@
+Libs: -L${libdir} -lobs @_LINKED_LIBRARIES@