Fix pkg-config file generation regression

Fixes regression cased by 37c93ba031.

Fixes #664.
Closes #679.

CMakeLists.txt

@@ -50,6 +50,13 @@ if (BUILD_SHARED_LIBS)
     set(_GLFW_BUILD_DLL 1)
 endif()
 
+if (BUILD_SHARED_LIBS AND UNIX)
+    # On Unix-like systems, shared libraries can use the soname system.
+    set(GLFW_LIB_NAME glfw)
+else()
+    set(GLFW_LIB_NAME glfw3)
+endif()
+
 if (GLFW_USE_WAYLAND)
     set(GLFW_USE_EGL ON)
 elseif (GLFW_USE_MIR)

src/CMakeLists.txt

@@ -52,6 +52,7 @@ endif()
 
 add_library(glfw ${glfw_SOURCES} ${glfw_HEADERS})
 set_target_properties(glfw PROPERTIES
+                      OUTPUT_NAME ${GLFW_LIB_NAME}
                       VERSION ${GLFW_VERSION}
                       SOVERSION ${GLFW_VERSION_MAJOR}
                       POSITION_INDEPENDENT_CODE ON
@@ -105,13 +106,6 @@ if (MSVC)
     target_compile_definitions(glfw PRIVATE _CRT_SECURE_NO_WARNINGS)
 endif()
 
-if (BUILD_SHARED_LIBS AND UNIX)
-    # On Unix-like systems, shared libraries can use the soname system.
-    set_target_properties(glfw PROPERTIES OUTPUT_NAME glfw)
-else()
-    set_target_properties(glfw PROPERTIES OUTPUT_NAME glfw3)
-endif()
-
 if (GLFW_INSTALL)
     install(TARGETS glfw EXPORT glfwTargets DESTINATION lib${LIB_SUFFIX})
 endif()