diff --git a/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake b/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
--- a/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
+++ b/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
@@ -7,7 +7,7 @@
 
 if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
   set(ALL_CPU_FEATURES SSE2 SSE4_2 AVX2 AVX512F)
-  set(LIBC_COMPILE_OPTIONS_NATIVE -march=native)
+  # set(LIBC_COMPILE_OPTIONS_NATIVE -march=native)
 elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   set(LIBC_COMPILE_OPTIONS_NATIVE -mcpu=native)
 endif()
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
new file mode 100644
--- /dev/null
+++ b/libc/config/linux/arm/entrypoints.txt
@@ -0,0 +1,86 @@
+set(TARGET_LIBC_ENTRYPOINTS
+    # ctype.h entrypoints
+    libc.src.ctype.isalnum
+    libc.src.ctype.isalpha
+    libc.src.ctype.isascii
+    libc.src.ctype.isblank
+    libc.src.ctype.iscntrl
+    libc.src.ctype.isdigit
+    libc.src.ctype.isgraph
+    libc.src.ctype.islower
+    libc.src.ctype.isprint
+    libc.src.ctype.ispunct
+    libc.src.ctype.isspace
+    libc.src.ctype.isupper
+    libc.src.ctype.isxdigit
+    libc.src.ctype.toascii
+    libc.src.ctype.tolower
+    libc.src.ctype.toupper
+
+    # string.h entrypoints
+    libc.src.string.bcmp
+    libc.src.string.bzero
+    libc.src.string.memccpy
+    libc.src.string.memchr
+    libc.src.string.memcmp
+    libc.src.string.memcpy
+    libc.src.string.memmove
+    libc.src.string.mempcpy
+    libc.src.string.memrchr
+    libc.src.string.memset
+    libc.src.string.stpcpy
+    libc.src.string.stpncpy
+    libc.src.string.strcat
+    libc.src.string.strchr
+    libc.src.string.strcmp
+    libc.src.string.strcpy
+    libc.src.string.strcspn
+    libc.src.string.strlen
+    libc.src.string.strncat
+    libc.src.string.strncmp
+    libc.src.string.strncpy
+    libc.src.string.strnlen
+    libc.src.string.strpbrk
+    libc.src.string.strrchr
+    libc.src.string.strspn
+    libc.src.string.strstr
+    libc.src.string.strtok
+    libc.src.string.strtok_r
+
+    # inttypes.h entrypoints
+    libc.src.inttypes.imaxdiv
+
+    # stdlib.h entrypoints
+    libc.src.stdlib.abs
+    libc.src.stdlib.bsearch
+    libc.src.stdlib.div
+    libc.src.stdlib.labs
+    libc.src.stdlib.ldiv
+    libc.src.stdlib.llabs
+    libc.src.stdlib.lldiv
+    libc.src.stdlib.qsort
+)
+
+set(TARGET_LIBM_ENTRYPOINTS
+    # math.h entrypoints
+    libc.src.math.cosf
+    libc.src.math.fabs
+    libc.src.math.fabsf
+    libc.src.math.fabsl
+    libc.src.math.fdim
+    libc.src.math.fdimf
+    libc.src.math.fdiml
+    libc.src.math.fmax
+    libc.src.math.fmaxf
+    libc.src.math.fmaxl
+    libc.src.math.fmin
+    libc.src.math.fminf
+    libc.src.math.fminl
+    libc.src.math.sincosf
+    libc.src.math.sinf
+)
+
+set(TARGET_LLVMLIBC_ENTRYPOINTS
+  ${TARGET_LIBC_ENTRYPOINTS}
+  ${TARGET_LIBM_ENTRYPOINTS}
+)
diff --git a/libc/config/linux/arm/headers.txt b/libc/config/linux/arm/headers.txt
new file mode 100644
--- /dev/null
+++ b/libc/config/linux/arm/headers.txt
@@ -0,0 +1,9 @@
+set(TARGET_PUBLIC_HEADERS
+    libc.include.ctype
+    libc.include.errno
+    libc.include.fenv
+    libc.include.inttypes
+    libc.include.math
+    libc.include.stdlib
+    libc.include.string
+)
diff --git a/libc/src/__support/CPP/TypeTraits.h b/libc/src/__support/CPP/TypeTraits.h
--- a/libc/src/__support/CPP/TypeTraits.h
+++ b/libc/src/__support/CPP/TypeTraits.h
@@ -49,8 +49,11 @@
       IsSameV<unsigned short, TypeNoCV> || IsSameV<int, TypeNoCV> ||
       IsSameV<unsigned int, TypeNoCV> || IsSameV<long, TypeNoCV> ||
       IsSameV<unsigned long, TypeNoCV> || IsSameV<long long, TypeNoCV> ||
-      IsSameV<unsigned long long, TypeNoCV> || IsSameV<bool, TypeNoCV> ||
-      IsSameV<__uint128_t, TypeNoCV> || IsSameV<__int128_t, TypeNoCV>;
+      IsSameV<unsigned long long, TypeNoCV> || IsSameV<bool, TypeNoCV>
+#ifdef __SIZEOF_INT128__
+      || IsSameV<__uint128_t, TypeNoCV> || IsSameV<__int128_t, TypeNoCV>
+#endif // __uint128_t
+      ;
 };
 
 template <typename T> struct IsPointerTypeNoCV : public FalseValue {};
diff --git a/libc/src/__support/FPUtil/FloatProperties.h b/libc/src/__support/FPUtil/FloatProperties.h
--- a/libc/src/__support/FPUtil/FloatProperties.h
+++ b/libc/src/__support/FPUtil/FloatProperties.h
@@ -59,6 +59,10 @@
   static constexpr BitsType QUIET_NAN_MASK = 0x0008000000000000ULL;
 };
 
+// I don't know if this is true on ARM32, but otherwise it tries to use
+// uint128 and that doesn't work.
+#define LONG_DOUBLE_IS_DOUBLE 1
+
 #if defined(LONG_DOUBLE_IS_DOUBLE)
 // Properties for numbers represented in 64 bits long double on Windows
 // platform.
diff --git a/libc/src/string/memory_utils/utils.h b/libc/src/string/memory_utils/utils.h
--- a/libc/src/string/memory_utils/utils.h
+++ b/libc/src/string/memory_utils/utils.h
@@ -17,6 +17,8 @@
 // time.
 #if defined(LLVM_LIBC_ARCH_AARCH64) || defined(LLVM_LIBC_ARCH_X86)
 #define LLVM_LIBC_CACHELINE_SIZE 64
+#elif defined(LLVM_LIBC_ARCH_ARM)
+#define LLVM_LIBC_CACHELINE_SIZE 32 // This number is just a guess.
 #else
 #error "Unsupported platform for memory functions."
 #endif
diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -371,7 +371,7 @@
 
 
 # Define LLVM_HAS_ATOMICS if gcc or MSVC atomic builtins are supported.
-include(CheckAtomic)
+# include(CheckAtomic)
 
 if( LLVM_ENABLE_PIC )
   set(ENABLE_PIC 1)