When building using CMake with ICU enabled on a default installation of Mac OS 10.6.8, with a case-insensitive HFS+ formatted hard drive, JavaScriptCore/wtf/unicode/UTF8.h gets included from the ICU header utf.h. But the ICU header utf8.h should be included instead of JavaScriptCore/wtf/unicode/UTF8.h. One idea to avoid this naming collision is to rename JavaScriptCore/wtf/unicode/UTF8.h to, say, JavaScriptCore/wtf/unicode/WTFUTF8.h. I'm not very happy with this idea and would greatly appreciate any insight/suggestions into how to resolve this issue. I tried changing the CMake build system so that it uses the ICU headers in JavaScriptCore/icu and WebCore/icu when building JavaScriptCore and WebCore, respectively, but the same issue persists. That is, when JavaScriptCore/icu/unicode/utf.h includes utf8.h it includes JavaScriptCore/wtf/unicode/UTF8.h instead of JavaScriptCore/icu/unicode/utf8.h. From briefly looking at the xcodebuild output of the Apple Mac build I noticed that it includes -I. and -Iicu among the include directories. I also tried a similar approach to no avail. Additional remarks: Inserting a #pragma message directive to more easily see this issue and compiling Source/WebCore/platform/text/TextCodecUTF8.cpp, I get the following output: ... [ 29%] In file included from /Users/dbates/Desktop/RIM/staging/usr/include/unicode/utf.h:230, from /Users/dbates/Desktop/RIM/staging/usr/include/unicode/utypes.h:37, from /Users/dbates/Desktop/RIM/staging/usr/include/unicode/uchar.h:26, from /Users/dbates/Desktop/RIM/webkit/Source/JavaScriptCore/wtf/unicode/icu/UnicodeIcu.h:27, from /Users/dbates/Desktop/RIM/webkit/Source/JavaScriptCore/wtf/unicode/Unicode.h:31, from /Users/dbates/Desktop/RIM/webkit/Source/WebCore/platform/text/TextCodec.h:35, from /Users/dbates/Desktop/RIM/webkit/Source/WebCore/platform/text/TextCodecUserDefined.h:29, from /Users/dbates/Desktop/RIM/webkit/Source/WebCore/platform/text/TextCodecUserDefined.cpp:27: /Users/dbates/Desktop/RIM/webkit/Source/JavaScriptCore/wtf/unicode/utf8.h:30: note: #pragma message: JavaScriptCore/wtf/unicode/UTF8.h Building CXX object WebCore/CMakeFiles/webcore.dir/platform/text/transcoder/FontTranscoder.cpp.o In file included from /Users/dbates/Desktop/RIM/webkit/Source/WebCore/platform/text/TextCodecUTF8.cpp:27: /Users/dbates/Desktop/RIM/webkit/Source/WebCore/platform/text/TextCodecUTF8.h:50: error: 'U8_MAX_LENGTH' was not declared in this scope ... The directory /Users/dbates/Desktop/RIM/staging/usr/include is specified to g++ using -isystem so that it is included in the system header search path. Both RIM/staging/usr/include/unicode/utf.h and JavaScriptCore/icu/unicode/utf.h include utf8.h as follows: /* include the utfXX.h ------------------------------------------------------ */ #include "unicode/utf8.h" #include "unicode/utf16.h" (http://trac.webkit.org/browser/trunk/Source/JavaScriptCore/icu/unicode/utf.h?rev=74855#L215) Notice the use of a relative include path. Changing "unicode/utf8.h" to "utf8.h" above resolves the build issue but it's undesirable to change these ICU headers as they are from a third-party.