Add iOS build support for USD Core

This PR adds **Core** iOS support to the OpenUSD project. This does not include Imaging, and any Imaging related components at this time. Imaging will be added in a follow up PR. MaterialX is also disabled as requested and the upgrade will be handled in a follow up PR.

It is a minimal version of #2455 against the latest `dev` branch.
Changes include:
* Using latest dev branch
* No imaging support. Will be added in a follow up PR.
* Makes use of CMake's inbuilt iOS support, negating the need for toolchain support
* Structures the code in such a way that we can add support for other iOS derived platforms+simulator in future PRs
* Swaps `ARCH_OS_IOS` with `ARCH_OS_IPHONE` to align with compiler directives. IPHONE refers to all derivative platforms, whereas iOS refers to only iPhone/iPad (Confusing but the case for historical reasons as [documented here](https://chaosinmotion.com/2021/08/02/things-to-remember-compiler-conditionals-for-macos-ios-etc/))
* TBB requires SDKROOT to be passed in or it can often go off and find some random compiler toolchain and fail.
* Add APPLE_EMBEDDED boolean to designate when using the CMake supported cross compilation targets. Added in Options.cmake so it can be used to configure defaults properly.

Author: dgovil

build_scripts/apple_utils.py

@@ -19,6 +19,8 @@
 import shlex
 import subprocess
 from typing import Optional, List
+import re
+from typing import Optional, List
 
 TARGET_NATIVE = "native"
 TARGET_X86 = "x86_64"
@@ -163,26 +165,63 @@ def ExtractFilesRecursive(path, cond):
                 files.append(os.path.join(r, file))
     return files
 
-def CodesignFiles(files):
-    SDKVersion  = subprocess.check_output(
-        ['xcodebuild', '-version']).strip()[6:10]
-    codeSignIDs = subprocess.check_output(
-        ['security', 'find-identity', '-vp', 'codesigning'])
+def _GetCodeSignStringFromTerminal():
+    codeSignIDs = GetCommandOutput(['security', 'find-identity', '-vp', 'codesigning'])
+    return codeSignIDs
 
-    codeSignID = "-"
+def GetCodeSignID():
     if os.environ.get('CODE_SIGN_ID'):
-        codeSignID = os.environ.get('CODE_SIGN_ID')
-    elif float(SDKVersion) >= 11.0 and \
-                codeSignIDs.find(b'Apple Development') != -1:
-        codeSignID = "Apple Development"
-    elif codeSignIDs.find(b'Mac Developer') != -1:
-        codeSignID = "Mac Developer"
+        return os.environ.get('CODE_SIGN_ID')
+
+    codeSignIDs = _GetCodeSignStringFromTerminal()
+    if not codeSignIDs:
+        return "-"
+    for codeSignID in codeSignIDs.splitlines():
+        if "CSSMERR_TP_CERT_REVOKED" in codeSignID:
+            continue
+        if ")" not in codeSignID:
+            continue
+        codeSignID = codeSignID.split()[1]
+        break
+    else:
+        raise RuntimeError("Could not find a valid codesigning ID")
+
+    return codeSignID or "-"
+
+def GetCodeSignIDHash():
+    codeSignIDs = _GetCodeSignStringFromTerminal()
+    try:
+        return re.findall(r'\(.*?\)', codeSignIDs)[0][1:-1]
+    except:
+        raise Exception("Unable to parse codesign ID hash")
+
+def GetDevelopmentTeamID():
+    if os.environ.get("DEVELOPMENT_TEAM"):
+        return os.environ.get("DEVELOPMENT_TEAM")
+    codesignID = GetCodeSignIDHash()
+
+    certs = subprocess.check_output(["security", "find-certificate", "-c", codesignID, "-p"])
+    subject = GetCommandOutput(["openssl", "x509", "-subject"], input=certs)
+    subject = subject.splitlines()[0]
+
+    # Extract the Organizational Unit (OU field) from the cert
+    try:
+        team = [elm for elm in subject.split(
+            '/') if elm.startswith('OU')][0].split('=')[1]
+        if team is not None and team != "":
+            return team
+    except Exception as ex:
+        raise Exception("No development team found with exception " + ex)
+
+def CodesignFiles(files):
+    codeSignID = GetCodeSignID()
 
     for f in files:
         subprocess.call(['codesign', '-f', '-s', '{codesignid}'
-                              .format(codesignid=codeSignID), f],
+                        .format(codesignid=codeSignID), f],
                         stdout=devout, stderr=devout)
 
+
 def Codesign(install_path, verbose_output=False):
     if not MacOS():
         return False

build_scripts/build_usd.py

@@ -955,7 +955,7 @@ def InstallBoost(context, force, buildArgs):
 
 def InstallOneTBB(context, force, buildArgs):
     with CurrentWorkingDirectory(DownloadURL(ONETBB_URL, context, force)):
-        RunCMake(context, force, 
+        RunCMake(context, force,
                  ['-DTBB_TEST=OFF',
                   '-DTBB_STRICT=OFF'] + buildArgs)
 
@@ -1326,12 +1326,12 @@ def InstallOpenImageIO(context, force, buildArgs):
                      '-DUSE_PYTHON=OFF',
                      '-DSTOP_ON_WARNING=OFF']
 
-        # OIIO's FindOpenEXR module circumvents CMake's normal library 
+        # OIIO's FindOpenEXR module circumvents CMake's normal library
         # search order, which causes versions of OpenEXR installed in
         # /usr/local or other hard-coded locations in the module to
-        # take precedence over the version we've built, which would 
-        # normally be picked up when we specify CMAKE_PREFIX_PATH. 
-        # This may lead to undefined symbol errors at build or runtime. 
+        # take precedence over the version we've built, which would
+        # normally be picked up when we specify CMAKE_PREFIX_PATH.
+        # This may lead to undefined symbol errors at build or runtime.
         # So, we explicitly specify the OpenEXR we want to use here.
         extraArgs.append('-DOPENEXR_ROOT="{instDir}"'
                          .format(instDir=context.instDir))