build: Minor cleanup and a disappointing workaround for iOS cross-compiling toolchain issues I don't understand.

GNUmakefile

@@ -246,8 +246,8 @@ $(IOS_TARGETS): CC = xcrun --sdk iphoneos clang -isysroot $(IOS_SYSROOT) -arch a
 $(IOSSIM_TARGETS): IOSSIM_SYSROOT := $(shell xcrun --sdk iphonesimulator --show-sdk-path)
 $(IOSSIM_TARGETS): CC = xcrun --sdk iphonesimulator clang -isysroot $(IOSSIM_SYSROOT) -arch x86_64
 else ifeq ($(UNAME_S),Linux)
-$(IOS_TARGETS): CFLAGS += -isysroot deps/ios_toolchain/target/SDKs/iPhoneOS18.2.sdk -arch arm64
-$(IOS_TARGETS): LDFLAGS += -isysroot deps/ios_toolchain/target/SDKs/iPhoneOS18.2.sdk
+$(IOS_TARGETS): CFLAGS += -isysroot deps/ios_toolchain/target/SDK/iPhoneOS18.2.sdk -arch arm64 -DTARGET_OS_IPHONE=1
+$(IOS_TARGETS): LDFLAGS += -isysroot deps/ios_toolchain/target/SDK/iPhoneOS18.2.sdk
 $(IOS_TARGETS): CC = PATH=$$PATH:deps/ios_toolchain/target/bin deps/ios_toolchain/target/bin/arm-apple-darwin11-clang
 endif
 $(ANDROID_X86_64_TARGETS): ANDROID_NDK_TARGET_TRIPLE := x86_64-linux-android

src/ssb.tests.c

@@ -18,6 +18,10 @@
 
 #include "sodium/crypto_sign.h"
 
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
 #if !defined(_WIN32)
 #include <sys/wait.h>
 #endif

src/task.c

@@ -40,6 +40,10 @@
 #define WEXITSTATUS(x) (x)
 #endif
 
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
 #if !defined(__APPLE__) && !defined(__OpenBSD__)
 #include <malloc.h>
 #endif
@@ -726,7 +730,6 @@ static JSValue _tf_task_platform(JSContext* context, JSValueConst this_val, int
 #elif defined(__ANDROID__)
 	return JS_NewString(context, "android");
 #elif defined(__APPLE__)
-#include <TargetConditionals.h>
 #if TARGET_OS_IPHONE
 	return JS_NewString(context, "iphone");
 #else