qt5base-lts/mkspecs/features/mac/sdk.prf

isEmpty(QMAKE_MAC_SDK): \
    error("QMAKE_MAC_SDK must be set when using CONFIG += sdk.")

contains(QMAKE_MAC_SDK, .*/.*): \
    error("QMAKE_MAC_SDK can only contain short-form SDK names (eg. macosx, iphoneos)")

defineReplace(xcodeSDKInfo) {
    info = $$1
    equals(info, "Path"): \
        infoarg = --show-sdk-path
    equals(info, "PlatformPath"): \
        infoarg = --show-sdk-platform-path
    equals(info, "SDKVersion"): \
        infoarg = --show-sdk-version
    sdk = $$2
    isEmpty(sdk): \
        sdk = $$QMAKE_MAC_SDK

    isEmpty(QMAKE_MAC_SDK.$${sdk}.$${info}) {
        QMAKE_MAC_SDK.$${sdk}.$${info} = $$system("/usr/bin/xcrun --sdk $$sdk $$infoarg 2>/dev/null")
        # --show-sdk-platform-path won't work for Command Line Tools; this is fine
        # only used by the XCTest backend to testlib
        isEmpty(QMAKE_MAC_SDK.$${sdk}.$${info}):if(!isEmpty(QMAKE_XCODEBUILD_PATH)|!equals(infoarg, "--show-sdk-platform-path")): \
            error("Could not resolve SDK $$info for \'$$sdk\' using $$infoarg")
        cache(QMAKE_MAC_SDK.$${sdk}.$${info}, set stash, QMAKE_MAC_SDK.$${sdk}.$${info})
    }

    return($$eval(QMAKE_MAC_SDK.$${sdk}.$${info}))
}

QMAKE_MAC_SDK_PATH = $$xcodeSDKInfo(Path)
QMAKE_MAC_SDK_PLATFORM_PATH = $$xcodeSDKInfo(PlatformPath)
QMAKE_MAC_SDK_VERSION = $$xcodeSDKInfo(SDKVersion)

QMAKESPEC_NAME = $$basename(QMAKESPEC)

# Resolve SDK version of various tools
for(tool, $$list(QMAKE_CC QMAKE_CXX QMAKE_FIX_RPATH QMAKE_AR QMAKE_RANLIB QMAKE_LINK QMAKE_LINK_SHLIB QMAKE_ACTOOL QMAKE_LINK_C QMAKE_LINK_C_SHLIB)) {
    tool_variable = QMAKE_MAC_SDK.$${QMAKESPEC_NAME}.$${QMAKE_MAC_SDK}.$${tool}
    !isEmpty($$tool_variable) {
        $$tool = $$eval($$tool_variable)
        next()
    }

    value = $$eval($$tool)
    isEmpty(value): next()

    sysrooted = $$system("/usr/bin/xcrun -sdk $$QMAKE_MAC_SDK -find $$first(value) 2>/dev/null")
    isEmpty(sysrooted): next()

    $$tool = $$sysrooted $$member(value, 1, -1)
    cache($$tool_variable, set stash, $$tool)
}