Fix code signing issues on macOS with Xcode 12.2 (#744)

It turned out that enabling Bitcode *project-wide* is a bad idea because
for some reason it causes code signing issues when preparing macOS apps
for distribution.

Not only this glorious technology breaks iOS apps at times, the advent
Apple Silicon seems to making macOS and iOS really comptaible. I'd say,
bug-to-bug compatible!

So... if Bitcode metastasises into macOS builds, the apps exhibit
similar symptoms: everything seems to be fine, the app and its build
lead their normal life, right until the developer attempts to prepare
the app for distribution. Then it suddenly fails to code sign with
the following errors hidden deeply in logs:

    Running /usr/bin/codesign '-vvv' '--force' '--sign' '3356BDE5BC1F1235571602E373E6BA16B748CDF3' [...]
    [...].app/Contents/Frameworks/themis.framework/Versions/A: replacing existing signature
    [...].app/Contents/Frameworks/themis.framework/Versions/A: code object is not signed at all
    /usr/bin/codesign exited with 1

Well, that's enligtening!

Anyway. Once there is no mention of Bitcode whatsoever in the build
settings of macOS target for Themis framework, the applications can be
signed and everything seems to be okay.

Remove ENABLE_BITCODE setting from all macOS targets, leave it only for
iOS targets. The framework is built with YES (but of course!) and the
tests are built with NO, because the tests are bundles and they are not
compatible with Bitcode (and they are not capable of using it anyway).

Of course, we learn about this only with Xcode 12.2 RC which supports
Apple Silicon architecture. It's a long-standing Apple tradition to
change something up in code signing every 18 months, just to keep the
developers sharp.

CHANGELOG.md

@@ -22,6 +22,7 @@ _Code:_
   - Updated Objective-C examples (iOS and macOS, Carthage and CocoaPods) to showcase usage of the newest Secure Cell API: generating symmetric keys and using Secure Cell with Passphrase ([#688](https://github.com/cossacklabs/themis/pull/688)) and to use latest Themis 0.13.4 ([#701](https://github.com/cossacklabs/themis/pull/701), [#703](https://github.com/cossacklabs/themis/pull/703), [#706](https://github.com/cossacklabs/themis/pull/706), [#723](https://github.com/cossacklabs/themis/pull/723), [#724](https://github.com/cossacklabs/themis/pull/724), [#726](https://github.com/cossacklabs/themis/pull/726), [#740](https://github.com/cossacklabs/themis/pull/740)).
   - `TSSession` initializer now returns an error (`nil`) when given incorrect key type ([#710](https://github.com/cossacklabs/themis/pull/710)).
   - Improved compatibility with Xcode 12 ([#742](https://github.com/cossacklabs/themis/pull/742)).
+  - Fixed code signing issues on macOS with Xcode 12 ([#744](https://github.com/cossacklabs/themis/pull/744)).
 
 - **PHP**
 
@@ -49,6 +50,7 @@ _Code:_
   - Updated Swift examples (iOS and macOS, Carthage and CocoaPods) to showcase usage of the newest Secure Cell API: generating symmetric keys and using Secure Cell with Passphrase ([#688](https://github.com/cossacklabs/themis/pull/688)) and to use latest Themis 0.13.4 ([#701](https://github.com/cossacklabs/themis/pull/701), [#703](https://github.com/cossacklabs/themis/pull/703), [#706](https://github.com/cossacklabs/themis/pull/706), [#740](https://github.com/cossacklabs/themis/pull/740)).
   - `TSSession` initializer now returns an error (`nil`) when given incorrect key type ([#710](https://github.com/cossacklabs/themis/pull/710)).
   - Improved compatibility with Xcode 12 ([#742](https://github.com/cossacklabs/themis/pull/742)).
+  - Fixed code signing issues on macOS with Xcode 12 ([#744](https://github.com/cossacklabs/themis/pull/744)).
 
 _Infrastructure:_
 

Themis.xcodeproj/project.pbxproj

@@ -1375,7 +1375,6 @@
 				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 4;
 				DEBUG_INFORMATION_FORMAT = dwarf;
-				ENABLE_BITCODE = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
@@ -1442,7 +1441,6 @@
 				COPY_PHASE_STRIP = NO;
 				CURRENT_PROJECT_VERSION = 4;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
-				ENABLE_BITCODE = YES;
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
@@ -1544,6 +1542,7 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_BITCODE = YES;
 				EXCLUDED_ARCHS = "";
 				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "arm64 arm64e";
 				EXPORTED_SYMBOLS_FILE = "$(PROJECT_DIR)/src/wrappers/themis/Obj-C/exported.symbols";
@@ -1583,6 +1582,7 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_BITCODE = YES;
 				EXCLUDED_ARCHS = "";
 				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "arm64 arm64e";
 				EXPORTED_SYMBOLS_FILE = "$(PROJECT_DIR)/src/wrappers/themis/Obj-C/exported.symbols";
@@ -1614,7 +1614,6 @@
 		9F70B2C5241D0FEC009CB629 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Carthage/Build/Mac",
@@ -1637,7 +1636,6 @@
 		9F70B2C6241D0FEC009CB629 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Carthage/Build/Mac",
@@ -1772,7 +1770,6 @@
 		9F70B32F2420E176009CB629 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Carthage/Build/Mac",
@@ -1795,7 +1792,6 @@
 		9F70B3302420E176009CB629 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
 					"$(PROJECT_DIR)/Carthage/Build/Mac",