improve pkg-config file generation.

Fixes: #236

CMakeLists.txt

@@ -194,6 +194,9 @@ IF (UNIX AND NOT APPLE)
     MESSAGE(STATUS "M_LIBRARY: ${M_LIBRARY}")
     IF (NOT M_LIBRARY)
         SET(M_LIBRARY "")
+        SET(PKG_PRIVATELIBS "")
+    ELSE()
+        SET(PKG_PRIVATELIBS "-lm")
     ENDIF()
 ENDIF()
 

src/CMakeLists.txt

@@ -132,6 +132,10 @@ IF (WANT_DEVTEST)
 ENDIF()
 
 # prepare pkg-config file
+set(prefix ${CMAKE_INSTALL_PREFIX})
+set(exec_prefix "\${prefix}")
+set(includedir "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
+set(libdir "${CMAKE_INSTALL_FULL_LIBDIR}")
 CONFIGURE_FILE("wildmidi.pc.in" "${PROJECT_BINARY_DIR}/wildmidi.pc" @ONLY)
 
 INSTALL(TARGETS ${wildmidi_lib_install}

src/wildmidi.pc.in

@@ -1,15 +1,15 @@
 # WildMIDI pkg-config file
 
-prefix=@CMAKE_INSTALL_PREFIX@
-exec_prefix=${prefix}
-libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
-includedir=${exec_prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
 
 Name: WildMIDI
 Description: software synthesizer library
 Version: @WILDMIDI_VERSION@
 URL: https://github.com/Mindwerks/wildmidi
 
 Libs: -L${libdir} -lWildMidi
-Libs.private: -lm 
+Libs.private: @PKG_PRIVATELIBS@
 Cflags: -I${includedir}