diff --git a/.gitignore b/.gitignore
index 0c97ba5..5762dc8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 /lib
 /a
 /src/ciabatta.c
+/src/include/conf.h
 a.out
 *.a
 *.so
diff --git a/build.py b/build.py
index 7d9e23f..ff820a4 100755
--- a/build.py
+++ b/build.py
@@ -62,7 +62,7 @@ dependencies.append(args.compiler)
 
 
 # Figure out the flags
-includes = ['include']
+includes = ['src/include']
 cc = args.compiler
 cc_defines = []
 cc_flags = ['-nostdlib']
@@ -77,7 +77,6 @@ else: # 'debug'
     cc_defines.append('_DEBUG')
 if target != 'windows':
     cc_flags.append('-fpic')
-cc_defines.append(f'_CIA_OS_{target.upper()}')
 
 # Check dependencies
 print(colors.grey, '==> Checking dependencies...', colors.reset, end='', sep='')
@@ -188,6 +187,8 @@ except Exception as error:
     print(colors.red, f"  ERROR writing file '{ciabatta_header_path}':", sep='')
     print(f"  {error}", colors.reset)
     sys.exit(1)
+print(colors.grey, f"==> Generating cia-conf.h", colors.reset, sep='')
+
 
 def quote(s):
     return '"' + s + '"'
@@ -202,6 +203,18 @@ cc_flags_str = ' '.join(
                list(map(prefix_quote('-I '), includes)))
 
 print(colors.grey, f"==> Compiling {lib_file}", colors.reset, sep='')
+try:
+    with open(os.path.join('src', 'include', 'cia-conf.h'), 'w') as conf_file:
+        os_config = open(os.path.join('src', target, 'conf.h'))
+        conf_file.write('\n')
+        conf_file.write('// This file is AUTO-GENERATED\n')
+        conf_file.write('// See os folder (e.g. src/linux) for conf.h file\n')
+        conf_file.write(os_config.read())
+        os_config.close()
+except Exception as error:
+    print(colors.red, f"  ERROR writing file '{ciabatta_header_path}':", sep='')
+    print(f"  {error}", colors.reset)
+    sys.exit(1)
 
 def assemble(src, out):
     format = 'elf64'
diff --git a/src/include/cia-conf.h b/src/include/cia-conf.h
new file mode 100644
index 0000000..1f6f898
--- /dev/null
+++ b/src/include/cia-conf.h
@@ -0,0 +1,6 @@
+
+// This file is AUTO-GENERATED
+// See os folder (e.g. src/linux) for conf.h file
+
+#define _CIA_OS_LINUX
+#define _CIA_DATA_LP64
diff --git a/include/cia-def.h b/src/include/cia-def.h
similarity index 57%
rename from include/cia-def.h
rename to src/include/cia-def.h
index 750005b..03ea4f3 100644
--- a/include/cia-def.h
+++ b/src/include/cia-def.h
@@ -1,13 +1,8 @@
 
 #pragma once
 
-// Since we're re-defining noreturn below, this would mess
-// with __declspec(noreturn) in windows headers, which
-// is hidden behind a define. Good thing, because now we
-// can override that define over here.
-#if defined(_CIA_OS_WINDOWS)
-    #define DECLSPEC_NORETURN __declspec("noreturn")
-#endif
+// Include platform stuff
+#include <cia-conf.h>
 
 // Pre-C23 keyword macros and stddef
 #define static_assert _Static_assert
diff --git a/include/cia-mem.h b/src/include/cia-mem.h
similarity index 100%
rename from include/cia-mem.h
rename to src/include/cia-mem.h
diff --git a/include/ctype.h b/src/include/ctype.h
similarity index 100%
rename from include/ctype.h
rename to src/include/ctype.h
diff --git a/include/stdbool.h b/src/include/stdbool.h
similarity index 100%
rename from include/stdbool.h
rename to src/include/stdbool.h
diff --git a/include/stdint.h b/src/include/stdint.h
similarity index 91%
rename from include/stdint.h
rename to src/include/stdint.h
index 829b224..5ee6a51 100644
--- a/include/stdint.h
+++ b/src/include/stdint.h
@@ -5,9 +5,9 @@ static_assert(sizeof(char) == 1, "Char isn't 1 bytes long");
 static_assert(sizeof(short) == 2, "Short isn't 2 bytes long");
 static_assert(sizeof(int) == 4, "Int isn't 4 bytes long");
 static_assert(sizeof(long long int) == 8, "Long long isn't 8 bytes long");
-#if defined(_CIA_OS_LINUX)
+#if defined(_CIA_DATA_LP64)
     static_assert(sizeof(long) == 8, "Long on linux isn't 8 bytes");
-#elif defined(_CIA_OS_WINDOWS)
+#elif defined(_CIA_DATA_LLP64)
     static_assert(sizeof(long) == 4, "Long on windows isn't 4 bytes");
 #endif
 
@@ -17,14 +17,14 @@ typedef signed short int16_t;
 typedef unsigned short uint16_t;
 typedef signed int int32_t;
 typedef unsigned int uint32_t;
-#if defined(_CIA_OS_LINUX)
+#if defined(_CIA_DATA_LP64)
     typedef signed long int64_t;
     typedef unsigned long uint64_t;
-#elif defined(_CIA_OS_WINDOWS)
+#elif defined(_CIA_DATA_LLP64)
     typedef signed long long int64_t;
     typedef unsigned long long uint64_t;
 #else
-    #error "Platform not implemented"
+    #error "Data model not implemented"
 #endif
 
 typedef int8_t int_fast8_t, int_least8_t;
@@ -50,18 +50,18 @@ typedef uint64_t uintptr_t;
 #define UINT16_C(n)  (n)
 #define UINT32_C(n)  (n)
 
-#if defined(_CIA_OS_LINUX)
+#if defined(_CIA_DATA_LP64)
     #define INT64_C(n)   (n ## L)
     #define INTMAX_C(n)  (n ## L)
     #define UINT64_C(n)  (n ## UL)
     #define UINTMAX_C(n) (n ## UL)
-#elif defined(_CIA_OS_WINDOWS)
+#elif defined(_CIA_DATA_LLP64)
     #define INT64_C(n)   (n ## LL)
     #define INTMAX_C(n)  (n ## LL)
     #define UINT64_C(n)  (n ## ULL)
     #define UINTMAX_C(n) (n ## ULL)
 #else
-    #error "Platform functionality not defined"
+    #error "Data model not defined"
 #endif
 
 #define INT8_WIDTH          8
diff --git a/include/stdio.h b/src/include/stdio.h
similarity index 100%
rename from include/stdio.h
rename to src/include/stdio.h
diff --git a/include/stdlib.h b/src/include/stdlib.h
similarity index 100%
rename from include/stdlib.h
rename to src/include/stdlib.h
diff --git a/include/string.h b/src/include/string.h
similarity index 100%
rename from include/string.h
rename to src/include/string.h
diff --git a/include/tinyrt.h b/src/include/tinyrt.h
similarity index 100%
rename from include/tinyrt.h
rename to src/include/tinyrt.h
diff --git a/src/linux/conf.h b/src/linux/conf.h
new file mode 100644
index 0000000..d64652c
--- /dev/null
+++ b/src/linux/conf.h
@@ -0,0 +1,3 @@
+
+#define _CIA_OS_LINUX
+#define _CIA_DATA_LP64
diff --git a/src/windows/conf.h b/src/windows/conf.h
new file mode 100644
index 0000000..175909c
--- /dev/null
+++ b/src/windows/conf.h
@@ -0,0 +1,3 @@
+
+#define _CIA_OS_WINDOWS
+#define _CIA_DATA_LLP64