build: eliminate Xcode 9.1 warnings

- 3rdparty/libjasper/jas_getopt.c:129:25: warning: this function declaration is not a prototype [-Wstrict-prototypes]
- clang: warning: optimization flag '-fomit-frame-pointer' is not supported for target 'armv7' [-Wignored-optimization-argument]
- clang: warning: optimization flag '-fomit-frame-pointer' is not supported for target 'armv7s' [-Wignored-optimization-argument]
- backport IOS_ARCH toolchain option and setup CMAKE_SYSTEM_PROCESSOR:
  - adds '-mfpu=neon' compiler flag for ARM, SSE flags for i386/x86_64
  - fixed proper libpng compilation (no ARM asm)

3rdparty/libjasper/CMakeLists.txt

@@ -25,7 +25,7 @@ endif(WIN32 AND NOT MINGW)
 
 ocv_warnings_disable(CMAKE_C_FLAGS -Wno-implicit-function-declaration -Wno-uninitialized -Wmissing-prototypes
                                    -Wno-unused-but-set-parameter -Wmissing-declarations -Wunused -Wshadow -Wsign-compare)
-ocv_warnings_disable(CMAKE_C_FLAGS -Wunused-parameter) # clang
+ocv_warnings_disable(CMAKE_C_FLAGS -Wunused-parameter -Wstrict-prototypes) # clang
 ocv_warnings_disable(CMAKE_C_FLAGS /wd4013 /wd4018 /wd4101 /wd4244 /wd4267 /wd4715) # vs2005
 
 if(UNIX)

3rdparty/libpng/CMakeLists.txt

@@ -3,7 +3,7 @@
 #
 # ----------------------------------------------------------------------------
 
-if(ARM AND ENABLE_NEON AND NOT AARCH64)
+if(ARM AND ENABLE_NEON AND NOT AARCH64 AND NOT IOS)
   project(${PNG_LIBRARY} ASM)
 else()
   project(${PNG_LIBRARY})
@@ -14,7 +14,7 @@ ocv_include_directories("${CMAKE_CURRENT_SOURCE_DIR}" ${ZLIB_INCLUDE_DIR})
 file(GLOB lib_srcs *.c)
 file(GLOB lib_hdrs *.h)
 
-if(ARM AND ENABLE_NEON AND NOT AARCH64)
+if(ARM AND ENABLE_NEON AND NOT AARCH64 AND NOT IOS)
   list(APPEND lib_srcs arm/filter_neon.S arm/arm_init.c)
   add_definitions(-DPNG_ARM_NEON_OPT=2)
 else()

cmake/OpenCVCompilerOptions.cmake

@@ -164,7 +164,7 @@ if(CMAKE_COMPILER_IS_GNUCXX)
   # Other optimizations
   if(ENABLE_OMIT_FRAME_POINTER)
     add_extra_compiler_option(-fomit-frame-pointer)
-  else()
+  elseif(DEFINED ENABLE_OMIT_FRAME_POINTER)
     add_extra_compiler_option(-fno-omit-frame-pointer)
   endif()
   if(ENABLE_FAST_MATH)

platforms/ios/build_framework.py

@@ -49,6 +49,7 @@ def build_opencv(srcroot, buildroot, target, arch):
     # for some reason, if you do not specify CMAKE_BUILD_TYPE, it puts libs to "RELEASE" rather than "Release"
     cmakeargs = ("-GXcode " +
                 "-DCMAKE_BUILD_TYPE=Release " +
+                ("-DIOS_ARCH=%s " % arch) +
                 "-DCMAKE_TOOLCHAIN_FILE=%s/platforms/ios/cmake/Toolchains/Toolchain-%s_Xcode.cmake " +
                 "-DBUILD_opencv_world=ON " +
                 "-DCMAKE_C_FLAGS=\"-Wno-implicit-function-declaration\" " +

platforms/ios/cmake/Modules/Platform/iOS.cmake

@@ -43,7 +43,10 @@ set (no_warn "-Wno-unused-function -Wno-overloaded-virtual")
 set (CMAKE_C_FLAGS "${no_warn}")
 set (CMAKE_CXX_FLAGS "-stdlib=libc++ -fvisibility=hidden -fvisibility-inlines-hidden ${no_warn}")
 
-set (CMAKE_CXX_FLAGS_RELEASE "-DNDEBUG -O3 -fomit-frame-pointer -ffast-math")
+set(CMAKE_CXX_FLAGS_RELEASE "-DNDEBUG -O3 -ffast-math")
+if(NOT IOS_ARCH STREQUAL "armv7" AND NOT IOS_ARCH STREQUAL "armv7s")
+  set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -fomit-frame-pointer")
+endif()
 
 if (HAVE_FLAG_SEARCH_PATHS_FIRST)
     set (CMAKE_C_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_C_LINK_FLAGS}")

platforms/ios/cmake/Toolchains/Toolchain-iPhoneOS_Xcode.cmake

@@ -2,7 +2,10 @@ message (STATUS "Setting up iPhoneOS toolchain")
 set (IPHONEOS TRUE)
 
 # Standard settings
-set (CMAKE_SYSTEM_NAME iOS)
+set(CMAKE_SYSTEM_NAME iOS)
+set(CMAKE_SYSTEM_VERSION 6.0)
+set(CMAKE_SYSTEM_PROCESSOR "${IOS_ARCH}")
+
 # Include extra modules for the iOS platform files
 set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/platforms/ios/cmake/Modules")
 

platforms/ios/cmake/Toolchains/Toolchain-iPhoneSimulator_Xcode.cmake

@@ -2,7 +2,10 @@ message (STATUS "Setting up iPhoneSimulator toolchain")
 set (IPHONESIMULATOR TRUE)
 
 # Standard settings
-set (CMAKE_SYSTEM_NAME iOS)
+set(CMAKE_SYSTEM_NAME iOS)
+set(CMAKE_SYSTEM_VERSION 6.0)
+set(CMAKE_SYSTEM_PROCESSOR "${IOS_ARCH}")
+
 # Include extra modules for the iOS platform files
 set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/platforms/ios/cmake/Modules")