add watchOS(armv7k;arm64_32) and watchOS Simulator(i386) support

Author: garryyan

README.md

@@ -34,6 +34,8 @@ This will build and install the library for the given IOS_PLATFORM.
 * Set `-DIOS_PLATFORM` to "OS64" to build for Device (arm64 only)
 * Set `-DIOS_PLATFORM` to "TVOS" to build for tvOS (arm64)
 * Set `-DIOS_PLATFORM` to "SIMULATOR_TVOS" to build for tvOS Simulator (x86_64)
+* Set `-DIOS_PLATFORM` to "WATCHOS" to build for watchOS (armv7k)
+* Set `-DIOS_PLATFORM` to "SIMULATOR_WATCHOS" to build for watchOS Simulator (i386)
 
 ### Additional Options
 `-DENABLE_BITCODE=(BOOL)` - Enabled by default, specify FALSE or 0 to disable bitcode
@@ -42,7 +44,7 @@ This will build and install the library for the given IOS_PLATFORM.
 
 `-DENABLE_VISIBILITY=(BOOL)` - Disabled by default, specify TRUE or 1 to enable symbol visibility support
 
-`-DIOS_ARCH=(STRING)` - Valid values are: armv7, armv7s, arm64, i386, x86_64. By default it will build for all valid architectures based on `-DIOS_PLATFORM` (see above)
+`-DIOS_ARCH=(STRING)` - Valid values are: armv7, armv7s, arm64, i386, x86_64, armv7k, arm64_32. By default it will build for all valid architectures based on `-DIOS_PLATFORM` (see above)
 
 __*The resulting binary will consist of only one platform. To combine all platforms into the same fat-library, use the LIPO tool. More information on this is available on the net.*__
 

ios.toolchain.cmake

@@ -51,12 +51,14 @@
 #
 # The following variables control the behaviour of this toolchain:
 #
-# IOS_PLATFORM: OS (default) or SIMULATOR or SIMULATOR64 or TVOS or SIMULATOR_TVOS
+# IOS_PLATFORM: OS (default) or SIMULATOR or SIMULATOR64 or TVOS or SIMULATOR_TVOS or WATCHOS
 #    OS = Build for iPhoneOS.
 #    SIMULATOR = Build for x86 i386 iPhone Simulator.
 #    SIMULATOR64 = Build for x86_64 iPhone Simulator.
 #    TVOS = Build for AppleTVOS.
 #    SIMULATOR_TVOS = Build for x86_64 AppleTV Simulator.
+#    WATCHOS = Build for armv7k for WatchOS.
+#    SIMULATOR_WATCHOS = Build for i386 for Watch Simulator.
 # CMAKE_OSX_SYSROOT: Path to the iOS SDK to use.  By default this is
 #    automatically determined from IOS_PLATFORM and xcodebuild, but
 #    can also be manually specified (although this should not be required).
@@ -73,6 +75,8 @@
 #    SIMULATOR64 = x86_64
 #    TVOS = arm64
 #    SIMULATOR_TVOS = x86_64
+#    WATCHOS = armv7k
+#    SIMULATOR_WATCHOS = i386
 #
 # This toolchain defines the following variables for use externally:
 #
@@ -120,6 +124,8 @@ if (NOT DEFINED IOS_PLATFORM)
       set(IOS_PLATFORM "SIMULATOR")
     elseif (CMAKE_OSX_ARCHITECTURES MATCHES "x86_64")
       set(IOS_PLATFORM "SIMULATOR64")
+    elseif (CMAKE_OSX_ARCHITECTURES MATCHES "armv7k")
+      set(IOS_PLATFORM "WATCHOS")
     endif()
   endif()
   if (NOT IOS_PLATFORM)
@@ -160,6 +166,16 @@ elseif (IOS_PLATFORM STREQUAL "SIMULATOR_TVOS")
   if(NOT IOS_ARCH)
     set(IOS_ARCH x86_64)
   endif()
+elseif (IOS_PLATFORM STREQUAL "WATCHOS")
+  set(XCODE_IOS_PLATFORM watchos)
+  if(NOT IOS_ARCH)
+    set(IOS_ARCH armv7k)
+  endif()
+elseif (IOS_PLATFORM STREQUAL "SIMULATOR_WATCHOS")
+  set(XCODE_IOS_PLATFORM  watchsimulator)
+  if(NOT IOS_ARCH)
+    set(IOS_ARCH i386)
+  endif()
 else()
   message(FATAL_ERROR "Invalid IOS_PLATFORM: ${IOS_PLATFORM}")
 endif()
@@ -326,6 +342,12 @@ elseif (IOS_PLATFORM STREQUAL "TVOS")
 elseif (IOS_PLATFORM STREQUAL "SIMULATOR_TVOS")
   set(XCODE_IOS_PLATFORM_VERSION_FLAGS
     "-mtvos-simulator-version-min=${IOS_DEPLOYMENT_TARGET}")
+elseif (IOS_PLATFORM STREQUAL "WATCHOS")
+  set(XCODE_IOS_PLATFORM_VERSION_FLAGS
+    "-mwatchos-version-min=${IOS_DEPLOYMENT_TARGET}")
+elseif (IOS_PLATFORM STREQUAL "SIMULATOR_WATCHOS")
+  set(XCODE_IOS_PLATFORM_VERSION_FLAGS
+    "-mwatchos-simulator-version-min=${IOS_DEPLOYMENT_TARGET}")
 else()
   # SIMULATOR or SIMULATOR64 both use -mios-simulator-version-min.
   set(XCODE_IOS_PLATFORM_VERSION_FLAGS