Configure fmt.pc library name correctly.

Simplify getting library name.

Add FMT_DEBUG_SUFFIX variable.

CMakeLists.txt

@@ -174,9 +174,17 @@ target_include_directories(fmt PUBLIC
   $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:include>)
 
+set(FMT_DEBUG_POSTFIX d)
+
 set_target_properties(fmt PROPERTIES
   VERSION ${FMT_VERSION} SOVERSION ${CPACK_PACKAGE_VERSION_MAJOR}
-  DEBUG_POSTFIX d)
+  DEBUG_POSTFIX ${FMT_DEBUG_POSTFIX})
+
+# Set FMT_LIB_NAME for pkg-config fmt.pc.
+get_target_property(FMT_LIB_NAME fmt OUTPUT_NAME)
+if (CMAKE_BUILD_TYPE STREQUAL "Debug")
+  set(FMT_LIB_NAME ${FMT_LIB_NAME}${FMT_DEBUG_POSTFIX})
+endif ()
 
 if (BUILD_SHARED_LIBS)
   if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS")

support/cmake/fmt.pc.in

@@ -6,6 +6,6 @@ includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
 Name: fmt
 Description: A modern formatting library
 Version: @FMT_VERSION@
-Libs: -L${libdir} -lfmt
+Libs: -L${libdir} -l@FMT_LIB_NAME@
 Cflags: -I${includedir}