--- libmalloc/libmalloc-283.100.5/xcodeconfig/libmalloc.xcconfig
+++ libmalloc/libmalloc-374.40.6/xcodeconfig/libmalloc.xcconfig
@@ -58,7 +58,7 @@
 CLANG_WARN__DUPLICATE_METHOD_MATCH = YES
 
 // clang doesn't understand the simple_printf %y specifier
-WARNING_CFLAGS = -Wno-format-invalid-specifier -Wno-format-extra-args
+WARNING_CFLAGS = -Wno-format-invalid-specifier -Wno-format-extra-args -Watomic-implicit-seq-cst
 
 LLVM_LTO = LLVM_LTO_$(CURRENT_VARIANT)
 LLVM_LTO_normal = YES
@@ -69,40 +69,28 @@
 
 SIM_SUFFIX[sdk=*simulator*] = _sim
 LINK_WITH_STANDARD_LIBRARIES = NO
-OTHER_LDFLAGS = -all_load -L$(SDK_INSTALL_ROOT)/usr/lib/system -umbrella System $(CR_LDFLAGS) $(LIBCOMPILER_RT_LDFLAGS) $(LIBDYLD_LDFLAGS) $(LIBSYSCALL_LDFLAGS) $(LIBPLATFORM_LDFLAGS) $(PLATFORM_LDFLAGS) $(UPLINK_LDFLAGS) $(INTERPOSE_LDFLAGS) $(DIRTY_LDFLAGS)
+OTHER_LDFLAGS = -all_load -L$(SDK_INSTALL_ROOT)/usr/lib/system -umbrella System $(CR_LDFLAGS) $(LIBCOMPILER_RT_LDFLAGS) $(LIBDYLD_LDFLAGS) $(LIBSYSCALL_LDFLAGS) $(LIBPLATFORM_LDFLAGS) $(PLATFORM_LDFLAGS) $(LIBPTHREAD_LDFLAGS) $(LIBFEATUREFLAGS_LDFLAGS) $(UPLINK_LDFLAGS) $(INTERPOSE_LDFLAGS) $(DIRTY_LDFLAGS)
 LIBCOMPILER_RT_LDFLAGS = -lcompiler_rt
 LIBPLATFORM_LDFLAGS = -lsystem$(SIM_SUFFIX)_platform
 LIBSYSCALL_LDFLAGS = -lsystem$(SIM_SUFFIX)_kernel
+LIBPTHREAD_LDFLAGS = -lsystem$(SIM_SUFFIX)_pthread
 LIBDYLD_LDFLAGS = -ldyld
+
+LIBFEATUREFLAGS_LDFLAGS = -Wl,-upward-lsystem_featureflags
+LIBFEATUREFLAGS_LDFLAGS[sdk=macosx*][arch=i386] =
+LIBFEATUREFLAGS_LDFLAGS[sdk=driverkit*] =
+LIBFEATUREFLAGS_EXCLUDES =
+LIBFEATUREFLAGS_EXCLUDES[sdk=driverkit*] = libmalloc.plist
+
+EXCLUDED_SOURCE_FILE_NAMES = $(LIBFEATUREFLAGS_EXCLUDES)
 
 // TODO: Eliminate the crosslink between libmalloc and Libc (13046853)
 UPLINK_LDFLAGS = -Wl,-upward-lsystem_c
 
 INTERPOSE_LDFLAGS = -Wl,-interposable_list,$(SRCROOT)/xcodeconfig/interposable.list
 
-ORDER_FILE = $(SDKROOT)/$(APPLE_INTERNAL_DIR)/OrderFiles/$(PRODUCT_NAME).order
-ORDER_FILE[sdk=*simulator*] =
-ORDER_FILE[sdk=driverkit*] =
-
 DYLIB_CURRENT_VERSION = $(CURRENT_PROJECT_VERSION)
 
-// #ifndef __OPEN_SOURCE__
-CR_LDFLAGS = -lCrashReporterClient
-// on architectures with OSAtomic & os_unfair_lock dyld resolvers we cannot
-// inline and need to callout to libplatform symbols rdar://problem/30155088
-OSATOMIC_PREPROCESSOR_DEFINITIONS[arch=armv7] = $(OSATOMIC_PREPROCESSOR_DEFINITIONS_NOINLINE)
-OSATOMIC_PREPROCESSOR_DEFINITIONS[arch=armv7k] = $(OSATOMIC_PREPROCESSOR_DEFINITIONS_NOINLINE)
-OSATOMIC_PREPROCESSOR_DEFINITIONS[arch=arm64] = $(OSATOMIC_PREPROCESSOR_DEFINITIONS_NOINLINE)
-ARMV81_CFLAGS = -mcpu=monsoon
-
-MALLOC_RESOLVER_SOURCE_FILE_NAMES				= resolver.c
-
-COPY_HEADERS_RUN_UNIFDEF = YES
-COPY_HEADERS_UNIFDEF_FLAGS = $(COPY_HEADERS_UNIFDEF_FLAGS_$(RC_HIDE_HARDWARE_FALL_2018_IOS))
-COPY_HEADERS_UNIFDEF_FLAGS_ = -URC_HIDE_HARDWARE_FALL_2018_IOS
-COPY_HEADERS_UNIFDEF_FLAGS_1 = -DRC_HIDE_HARDWARE_FALL_2018_IOS
-
-// #endif __OPEN_SOURCE__
 
 SUPPORTS_TEXT_BASED_API = YES
 TAPI_VERIFY_MODE = Pedantic