Extract build configuration into a separate header and move it to the base lib

src/base/build_config.h

Index: src/base/build_config.h
diff --git a/src/base/build_config.h b/src/base/build_config.h
new file mode 100644
index 0000000000000000000000000000000000000000..ea4fe8484638eeb1165b06208176eec6e6445508
--- /dev/null
+++ b/src/base/build_config.h
@@ -0,0 +1,120 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_BASE_BUILD_CONFIG_H_
+#define V8_BASE_BUILD_CONFIG_H_
+
+#include "../../include/v8config.h"
+
+// Processor architecture detection.  For more info on what's defined, see:
+//   http://msdn.microsoft.com/en-us/library/b0084kay.aspx
+//   http://www.agner.org/optimize/calling_conventions.pdf
+//   or with gcc, run: "echo | gcc -E -dM -"
+#if defined(_M_X64) || defined(__x86_64__)
+#if defined(__native_client__)
+// For Native Client builds of V8, use V8_TARGET_ARCH_ARM, so that V8
+// generates ARM machine code, together with a portable ARM simulator
+// compiled for the host architecture in question.
+//
+// Since Native Client is ILP-32 on all architectures we use
+// V8_HOST_ARCH_IA32 on both 32- and 64-bit x86.
+#define V8_HOST_ARCH_IA32 1
+#define V8_HOST_ARCH_32_BIT 1
+#define V8_HOST_CAN_READ_UNALIGNED 1
+#else
+#define V8_HOST_ARCH_X64 1
+#define V8_HOST_ARCH_64_BIT 1
+#define V8_HOST_CAN_READ_UNALIGNED 1
+#endif  // __native_client__
+#elif defined(_M_IX86) || defined(__i386__)
+#define V8_HOST_ARCH_IA32 1
+#define V8_HOST_ARCH_32_BIT 1
+#define V8_HOST_CAN_READ_UNALIGNED 1
+#elif defined(__AARCH64EL__)
+#define V8_HOST_ARCH_ARM64 1
+#define V8_HOST_ARCH_64_BIT 1
+#define V8_HOST_CAN_READ_UNALIGNED 1
+#elif defined(__ARMEL__)
+#define V8_HOST_ARCH_ARM 1
+#define V8_HOST_ARCH_32_BIT 1
+#elif defined(__MIPSEB__) || defined(__MIPSEL__)
+#define V8_HOST_ARCH_MIPS 1
+#define V8_HOST_ARCH_32_BIT 1
+#else
+#error "Host architecture was not detected as supported by v8"
+#endif
+
+#if defined(__ARM_ARCH_7A__) || \
+    defined(__ARM_ARCH_7R__) || \
+    defined(__ARM_ARCH_7__)
+# define CAN_USE_ARMV7_INSTRUCTIONS 1
+# ifndef CAN_USE_VFP3_INSTRUCTIONS
+#  define CAN_USE_VFP3_INSTRUCTIONS
+# endif
+#endif
+
+
+// Target architecture detection. This may be set externally. If not, detect
+// in the same way as the host architecture, that is, target the native
+// environment as presented by the compiler.
+#if !V8_TARGET_ARCH_X64 && !V8_TARGET_ARCH_IA32 && !V8_TARGET_ARCH_X87 &&\
+    !V8_TARGET_ARCH_ARM && !V8_TARGET_ARCH_ARM64 && !V8_TARGET_ARCH_MIPS
+#if defined(_M_X64) || defined(__x86_64__)
+#define V8_TARGET_ARCH_X64 1
+#elif defined(_M_IX86) || defined(__i386__)
+#define V8_TARGET_ARCH_IA32 1
+#elif defined(__AARCH64EL__)
+#define V8_TARGET_ARCH_ARM64 1
+#elif defined(__ARMEL__)
+#define V8_TARGET_ARCH_ARM 1
+#elif defined(__MIPSEB__) || defined(__MIPSEL__)
+#define V8_TARGET_ARCH_MIPS 1
+#else
+#error Target architecture was not detected as supported by v8
+#endif
+#endif
+
+// Check for supported combinations of host and target architectures.
+#if V8_TARGET_ARCH_IA32 && !V8_HOST_ARCH_IA32
+#error Target architecture ia32 is only supported on ia32 host
+#endif
+#if V8_TARGET_ARCH_X64 && !V8_HOST_ARCH_X64
+#error Target architecture x64 is only supported on x64 host
+#endif
+#if (V8_TARGET_ARCH_ARM && !(V8_HOST_ARCH_IA32 || V8_HOST_ARCH_ARM))
+#error Target architecture arm is only supported on arm and ia32 host
+#endif
+#if (V8_TARGET_ARCH_ARM64 && !(V8_HOST_ARCH_X64 || V8_HOST_ARCH_ARM64))
+#error Target architecture arm64 is only supported on arm64 and x64 host
+#endif
+#if (V8_TARGET_ARCH_MIPS && !(V8_HOST_ARCH_IA32 || V8_HOST_ARCH_MIPS))
+#error Target architecture mips is only supported on mips and ia32 host
+#endif
+
+// Determine architecture endianness.
+#if V8_TARGET_ARCH_IA32
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif V8_TARGET_ARCH_X64
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif V8_TARGET_ARCH_ARM
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif V8_TARGET_ARCH_ARM64
+#define V8_TARGET_LITTLE_ENDIAN 1
+#elif V8_TARGET_ARCH_MIPS
+#if defined(__MIPSEB__)
+#define V8_TARGET_BIG_ENDIAN 1
+#else
+#define V8_TARGET_LITTLE_ENDIAN 1
+#endif
+#elif V8_TARGET_ARCH_X87
+#define V8_TARGET_LITTLE_ENDIAN 1
+#else
+#error Unknown target architecture endianness
+#endif
+
+#if V8_OS_MACOSX || defined(__FreeBSD__) || defined(__OpenBSD__)
+#define USING_BSD_ABI
+#endif
+
+#endif  // V8_BASE_BUILD_CONFIG_H_