add .pc generation for CMake build

CMakeLists.txt

@@ -11,8 +11,8 @@ if(APPLE)
 elseif(NOT WIN32)
     if(CMAKE_SYSTEM_NAME MATCHES "Linux")
         option(HIDAPI_WITH_HIDRAW "Build HIDRAW-based implementation of HIDAPI" ON)
+        option(HIDAPI_WITH_LIBUSB "Build LIBUSB-based implementation of HIDAPI" ON)
     endif()
-    option(HIDAPI_WITH_LIBUSB "Build LIBUSB-based implementation of HIDAPI" ON)
 endif()
 
 option(BUILD_SHARED_LIBS "When set: build shared version of the libraries, otherwise - static" ON)

libusb/CMakeLists.txt

@@ -34,4 +34,10 @@ if(HIDAPI_INSTALL_TARGETS)
     )
 endif()
 
+if(HIDAPI_LIBNAME_VERBOSE)
+    hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi-libusb.pc.in")
+else()
+    hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi.pc.in")
+endif()
+
 add_library(hidapi ALIAS hidapi_libusb)

linux/CMakeLists.txt

@@ -29,6 +29,8 @@ if(HIDAPI_INSTALL_TARGETS)
     )
 endif()
 
+hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi-hidraw.pc.in")
+
 if(NOT HIDAPI_WITH_LIBUSB)
     add_library(hidapi ALIAS hidapi_hidraw)
 endif()

mac/CMakeLists.txt

@@ -38,4 +38,6 @@ if(HIDAPI_INSTALL_TARGETS)
     )
 endif()
 
+hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi.pc.in")
+
 add_library(hidapi ALIAS hidapi_darwin)

pc/hidapi-hidraw.pc.in

@@ -5,6 +5,7 @@ includedir=@includedir@
 
 Name: hidapi-hidraw
 Description: C Library for USB/Bluetooth HID device access from Linux, Mac OS X, FreeBSD, and Windows. This is the hidraw implementation.
+URL: https://github.com/libusb/hidapi
 Version: @VERSION@
 Libs: -L${libdir} -lhidapi-hidraw
 Cflags: -I${includedir}/hidapi

pc/hidapi-libusb.pc.in

@@ -5,6 +5,7 @@ includedir=@includedir@
 
 Name: hidapi-libusb
 Description: C Library for USB HID device access from Linux, Mac OS X, FreeBSD, and Windows. This is the libusb implementation.
+URL: https://github.com/libusb/hidapi
 Version: @VERSION@
 Libs: -L${libdir} -lhidapi-libusb
 Cflags: -I${includedir}/hidapi

pc/hidapi.pc.in

@@ -5,6 +5,7 @@ includedir=@includedir@
 
 Name: hidapi
 Description: C Library for USB/Bluetooth HID device access from Linux, Mac OS X, FreeBSD, and Windows.
+URL: https://github.com/libusb/hidapi
 Version: @VERSION@
 Libs: -L${libdir} -lhidapi
 Cflags: -I${includedir}/hidapi

src/CMakeLists.txt

@@ -5,7 +5,7 @@ file(READ "${PROJECT_ROOT}/VERSION" VERSION_STR)
 string(REGEX MATCH "^([0-9]+\\.[0-9]+\\.[0-9]+)(.*)" VERSION_STR "${VERSION_STR}")
 
 set(VERSION "${CMAKE_MATCH_1}")
-set(VERSION_SUFFIX "${CMAKE_MATCH_2}")
+string(STRIP "${CMAKE_MATCH_2}" VERSION_SUFFIX)
 #
 
 project(hidapi VERSION "${VERSION}" LANGUAGES C)
@@ -15,17 +15,38 @@ project(hidapi VERSION "${VERSION}" LANGUAGES C)
 if(NOT DEFINED BUILD_SHARED_LIBS)
     set(BUILD_SHARED_LIBS ON)
 endif()
-if(NOT DEFINED HIDAPI_WITH_HIDRAW)
-    set(HIDAPI_WITH_HIDRAW ON)
-endif()
-if(NOT DEFINED HIDAPI_WITH_LIBUSB)
-    set(HIDAPI_WITH_LIBUSB ON)
-endif()
 if(NOT DEFINED HIDAPI_INSTALL_TARGETS)
     set(HIDAPI_INSTALL_TARGETS OFF)
 endif()
+if(NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
+    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+endif()
 
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+# Helper(s)
+
+function(hidapi_configure_pc PC_IN_FILE)
+    file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/pc")
+
+    set(VERSION "${VERSION}${VERSION_SUFFIX}")
+    set(prefix "${CMAKE_INSTALL_PREFIX}")
+    set(exec_prefix "\${prefix}")
+    if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+        set(libdir "${CMAKE_INSTALL_LIBDIR}")
+    else()
+        set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+    endif()
+    if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+        set(includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+    else()
+        set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+    endif()
+
+    get_filename_component(PC_IN_FILENAME "${PC_IN_FILE}" NAME_WE)
+    set(PC_FILE "${CMAKE_CURRENT_BINARY_DIR}/pc/${PC_IN_FILENAME}.pc")
+    configure_file("${PC_IN_FILE}" "${PC_FILE}" @ONLY)
+
+    install(FILES "${PC_FILE}" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig/")
+endfunction()
 
 # The library
 
@@ -42,15 +63,21 @@ if(WIN32)
 elseif(APPLE)
     add_subdirectory("${PROJECT_ROOT}/mac" mac)
 else()
+    if(NOT DEFINED HIDAPI_WITH_LIBUSB)
+        set(HIDAPI_WITH_LIBUSB ON)
+    endif()
     if(CMAKE_SYSTEM_NAME MATCHES "Linux")
-        if(HIDAPI_WITH_HIDRAW)
+        if(NOT DEFINED HIDAPI_WITH_HIDRAW OR HIDAPI_WITH_HIDRAW)
             add_subdirectory("${PROJECT_ROOT}/linux" linux)
         endif()
         set(HIDAPI_LIBNAME_VERBOSE ON)
     else()
+        set(HIDAPI_WITH_LIBUSB ON)
         set(HIDAPI_LIBNAME_VERBOSE OFF)
     endif()
     if(HIDAPI_WITH_LIBUSB)
         add_subdirectory("${PROJECT_ROOT}/libusb" libusb)
+    elseif(NOT TARGET hidapi_hidraw)
+        message(FATAL_ERROR "Select at least one option to build: HIDAPI_WITH_LIBUSB or HIDAPI_WITH_HIDRAW")
     endif()
 endif()

windows/CMakeLists.txt

@@ -24,4 +24,6 @@ if(HIDAPI_INSTALL_TARGETS)
     )
 endif()
 
+hidapi_configure_pc("${PROJECT_ROOT}/pc/hidapi.pc.in")
+
 add_library(hidapi ALIAS hidapi_winapi)