diff --git a/Cargo.lock b/Cargo.lock
index 23d4c6e1aa..bf133296d9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -164,6 +164,14 @@ name = "itoa"
 version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "lazy_static"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "spin 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.42"
@@ -378,6 +386,11 @@ dependencies = [
  "platform 0.1.0",
 ]
 
+[[package]]
+name = "spin"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "standalone-quote"
 version = "0.5.0"
@@ -403,6 +416,7 @@ dependencies = [
  "cbindgen 0.5.2",
  "errno 0.1.0",
  "fcntl 0.1.0",
+ "lazy_static 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "platform 0.1.0",
  "ralloc 1.0.0",
  "string 0.1.0",
@@ -660,6 +674,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 "checksum itoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c069bbec61e1ca5a596166e55dfe4773ff745c3d16b700013bcaff9a6df2c682"
+"checksum lazy_static 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "e6412c5e2ad9584b0b8e979393122026cdd6d2a80b933f890dcd694ddbe73739"
 "checksum libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)" = "b685088df2b950fccadf07a7187c8ef846a959c142338a48f9dc0b94517eb5f1"
 "checksum log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "e19e8d5c34a3e0e2223db8e060f9e8264aeeb5c5fc64a4ee9965c062211c024b"
 "checksum log 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6fddaa003a65722a7fb9e26b0ce95921fe4ba590542ced664d8ce2fa26f9f3ac"
@@ -676,6 +691,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum serde_derive 1.0.21 (registry+https://github.com/rust-lang/crates.io-index)" = "652bc323d694dc925829725ec6c890156d8e70ae5202919869cb00fe2eff3788"
 "checksum serde_derive_internals 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "32f1926285523b2db55df263d2aa4eb69ddcfa7a7eade6430323637866b513ab"
 "checksum serde_json 1.0.22 (registry+https://github.com/rust-lang/crates.io-index)" = "84b8035cabe9b35878adec8ac5fe03d5f6bc97ff6edd7ccb96b44c1276ba390e"
+"checksum spin 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14db77c5b914df6d6173dda9a3b3f5937bd802934fa5edaf934df06a3491e56f"
 "checksum standalone-quote 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "dcedac1d6d98e7e9d1d6e628f5635af9566688ae5f6cea70a3976f495ae8d839"
 "checksum standalone-syn 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)" = "115808f5187c07c23cb93eee49d542fae54c6e8285d3a24c6ff683fcde9243db"
 "checksum strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb4f380125926a99e52bc279241539c018323fab05ad6368b56f93d9369ff550"
diff --git a/Makefile b/Makefile
index 39d1183a56..2efbec4023 100644
--- a/Makefile
+++ b/Makefile
@@ -73,4 +73,4 @@ $(BUILD)/openlibm: openlibm
 	touch $@
 
 $(BUILD)/openlibm/libopenlibm.a: $(BUILD)/openlibm
-	make CC=$(CC) CFLAGS=-fno-stack-protector -C $< libopenlibm.a
+	make CC=$(CC) CPPFLAGS="-fno-stack-protector -I$(shell pwd)/include -I $(shell pwd)/target/include" -C $< libopenlibm.a
diff --git a/include/bits/float.h b/include/bits/float.h
index c62ae491dc..01e393eade 100644
--- a/include/bits/float.h
+++ b/include/bits/float.h
@@ -3,4 +3,51 @@
 
 #define FLT_ROUNDS (flt_rounds())
 
+// Shamelessly copy pasted from musl:
+
+#define FLT_RADIX 2
+
+#define FLT_TRUE_MIN 1.40129846432481707092e-45F
+#define FLT_MIN 1.17549435082228750797e-38F
+#define FLT_MAX 3.40282346638528859812e+38F
+#define FLT_EPSILON 1.1920928955078125e-07F
+
+#define FLT_MANT_DIG 24
+#define FLT_MIN_EXP (-125)
+#define FLT_MAX_EXP 128
+#define FLT_HAS_SUBNORM 1
+
+#define FLT_DIG 6
+#define FLT_DECIMAL_DIG 9
+#define FLT_MIN_10_EXP (-37)
+#define FLT_MAX_10_EXP 38
+
+#define DBL_TRUE_MIN 4.94065645841246544177e-324
+#define DBL_MIN 2.22507385850720138309e-308
+#define DBL_MAX 1.79769313486231570815e+308
+#define DBL_EPSILON 2.22044604925031308085e-16
+
+#define DBL_MANT_DIG 53
+#define DBL_MIN_EXP (-1021)
+#define DBL_MAX_EXP 1024
+#define DBL_HAS_SUBNORM 1
+
+#define DBL_DIG 15
+#define DBL_DECIMAL_DIG 17
+#define DBL_MIN_10_EXP (-307)
+#define DBL_MAX_10_EXP 308
+
+#define LDBL_HAS_SUBNORM 1
+#define LDBL_DECIMAL_DIG DECIMAL_DIG
+
+// TODO: Support more architectures than x86_64 here:
+#define LDBL_TRUE_MIN 3.6451995318824746025e-4951L
+#define LDBL_MIN     3.3621031431120935063e-4932L
+#define LDBL_MAX     1.1897314953572317650e+4932L
+#define LDBL_EPSILON 1.0842021724855044340e-19L
+
+#define LDBL_MANT_DIG 64
+#define LDBL_MIN_EXP (-16381)
+#define LDBL_MAX_EXP 16384
+
 #endif
diff --git a/include/limits.h b/include/limits.h
index e69de29bb2..c85b58fa1d 100644
--- a/include/limits.h
+++ b/include/limits.h
@@ -0,0 +1,25 @@
+#define MB_LEN_MAX 4 // unicode
+
+#define CHAR_BIT __CHAR_BIT__
+#define CHAR_MAX __CHAR_MAX__
+#define CHAR_MIN 0
+#define INT_MAX __INT_MAX__
+#define INT_MIN (-INT_MAX - 1)
+#define LLONG_MAX __LONG_LONG_MAX__
+#define LLONG_MIN (-LLONG_MAX - 1)
+#define LONG_BIT __LONG_BIT__
+#define LONG_MAX __LONG_MAX__
+#define LONG_MIN (-LONG_MAX - 1)
+#define SCHAR_MAX __SCHAR_MAX__
+#define SCHAR_MIN (-SCHAR_MAX - 1)
+#define SHRT_MAX __SHRT_MAX__
+#define SHRT_MIN (-SHRT_MAX - 1)
+
+// TODO: These might not be accurate on all platforms
+#define SSIZE_MAX ((1 << 64 - 1) - 1)
+#define UCHAR_MAX 255
+#define UINT_MAX ((1 << 32) - 1)
+#define ULLONG_MAX ((1 << 64) - 1)
+#define ULONG_MAX ((1 << 64) - 1)
+#define USHRT_MAX ((1 << 16) - 1)
+#define WORD_BIT 32