* Add pkg-config file, allowing for build-system agnostic dependencies

* Define LIB_INSTALL_DIR cache variable, allowing for multilib installations
* Discover BLAS and LAPACK via pkg-config if possible
* Fix incorrect toolchain variables in "dlib/test/makefile"

dlib/CMakeLists.txt

@@ -79,6 +79,7 @@ if (NOT TARGET dlib)
    set (DLIB_LINK_WITH_SQLITE3_STR
    "Disable this if you don't want to link against sqlite3" )
    #set (DLIB_USE_FFTW_STR "Disable this if you don't want to link against fftw" )
+   set (LIB_INSTALL_DIR lib CACHE STRING "Install location of libraries (e.g. lib32 or lib64 for multilib installations)")
 
    option(DLIB_ISO_CPP_ONLY ${DLIB_ISO_CPP_ONLY_STR} OFF)
    toggle_preprocessor_switch(DLIB_ISO_CPP_ONLY)
@@ -308,6 +309,7 @@ if (NOT TARGET dlib)
          if (PNG_FOUND AND LIBPNG_IS_GOOD)
             include_directories(${PNG_INCLUDE_DIR})
             set (dlib_needed_libraries ${dlib_needed_libraries} ${PNG_LIBRARY})
+            set(REQUIRES_LIBS " libpng")
          else()
             # If we can't find libpng then statically compile it in.
             include_directories(external/libpng external/zlib)
@@ -343,6 +345,7 @@ if (NOT TARGET dlib)
                external/zlib/uncompr.c
                external/zlib/zutil.c
                )
+            set(REQUIRES_LIBS "")
          endif()
          set(source_files ${source_files}
             image_loader/png_loader.cpp
@@ -575,8 +578,8 @@ if (NOT TARGET dlib)
            install(TARGETS dlib dlib_shared
                    EXPORT dlib 
                    RUNTIME DESTINATION bin # Windows (including cygwin) considers .dll to be runtime artifacts
-                   LIBRARY DESTINATION lib
-                   ARCHIVE DESTINATION lib)
+                   LIBRARY DESTINATION "${LIB_INSTALL_DIR}"
+                   ARCHIVE DESTINATION "${LIB_INSTALL_DIR}")
        else()
            install(TARGETS dlib
                    EXPORT dlib 
@@ -601,7 +604,7 @@ if (NOT TARGET dlib)
 
        ## Config.cmake generation and installation
 
-       set(ConfigPackageLocation lib/cmake/dlib)
+       set(ConfigPackageLocation "${LIB_INSTALL_DIR}/cmake/dlib")
        install(EXPORT dlib
             NAMESPACE dlib::
             DESTINATION ${ConfigPackageLocation})
@@ -620,6 +623,13 @@ if (NOT TARGET dlib)
                     "${CMAKE_CURRENT_BINARY_DIR}/config/dlibConfig.cmake" 
                     "${CMAKE_CURRENT_BINARY_DIR}/config/dlibConfigVersion.cmake" 
                DESTINATION ${ConfigPackageLocation})
+
+       ## dlib-1.pc generation and installation
+
+       configure_file("dlib.pc.in" "dlib-1.pc" @ONLY)
+       install(FILES "${CMAKE_CURRENT_BINARY_DIR}/dlib-1.pc"
+           DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+
    endif()
 
 endif()

dlib/cmake_find_blas.txt

@@ -40,6 +40,20 @@ if (UNIX)
         return()
     endif()
 
+    # First, search for libraries via pkg-config, which is the cleanest path
+    find_package(PkgConfig)
+    pkg_check_modules(BLAS_REFERENCE cblas)
+    pkg_check_modules(LAPACK_REFERENCE lapack)
+    if (BLAS_REFERENCE_FOUND AND LAPACK_REFERENCE_FOUND)
+        set(blas_libraries "${BLAS_REFERENCE_LDFLAGS}")
+        set(lapack_libraries "${LAPACK_REFERENCE_LDFLAGS}")
+        set(blas_found 1)
+        set(lapack_found 1)
+        set(REQUIRES_LIBS "${REQUIRES_LIBS} cblas lapack")
+        message(STATUS "Found BLAS and LAPACK via pkg-config")
+        return()
+    endif()
+
     include(CheckTypeSize)
     check_type_size( "void*" SIZE_OF_VOID_PTR)
 

dlib/dlib.pc.in

+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+libdir=${exec_prefix}/@LIB_INSTALL_DIR@
+includedir=${prefix}/include
+
+Name: @PROJECT_NAME@
+Description: Numerical and networking C++ library
+Version: @VERSION@
+Libs: -L${libdir} -ldlib
+Cflags: -I${includedir}
+Requires:@REQUIRES_LIBS@

dlib/test/makefile

@@ -5,14 +5,15 @@
 TARGET = dtest 
 
 # these are the compile time flags passed to gcc
-CFLAGS = -ggdb  -DDEBUG -DDLIB_NO_GUI_SUPPORT  -I ../..  -Wall
+CXXFLAGS ?= -ggdb -Wall
+CPPFLAGS ?= -DDEBUG -DDLIB_NO_GUI_SUPPORT -I../..
 
 # These are the link time flags passed to gcc
 LFLAGS = -lpthread   -lnsl 
 
 # The name of the compiler.  If you only have one version of
 # gcc installed then you probably want to change this to just g++ 
-CC = nice g++
+CXX ?= nice g++
 
 ####################################################
 ####################################################
@@ -165,13 +166,9 @@ OBJ = $(TMP:.c=.o)
 
 $(TARGET): $(OBJ) 
 	@echo Linking $@
-	@$(CC) $(OBJ) $(LFLAGS) -o $@
+	@$(CXX) $(LDFLAGS) $(OBJ) $(LFLAGS) -o $@
 	@echo Build Complete
 
-.cpp.o: $<
-	@echo Compiling $<
-	@$(CC) -c $(CFLAGS) $< -o $@
-
 clean:
 	@rm -f $(OBJ) $(TARGET)
 	@echo All object files and binaries removed