WEBGL is temporarly disabled on win32-*, because it broked the bots.
Committed r92830: <http://trac.webkit.org/changeset/92830>
The error message is the following: ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:13:2: error: #error Trying to build a posix specific file in a non-posix build. ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp: In function 'OS_TLSIndex OS_AllocTLSIndex()': ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:21:5: error: 'pthread_key_t' was not declared in this scope ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:21:19: error: expected ';' before 'pPoolIndex' ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:26:30: error: 'pPoolIndex' was not declared in this scope ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:26:46: error: 'pthread_key_create' was not declared in this scope ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp: In function 'bool OS_SetTLSValue(OS_TLSIndex, void*)': ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:43:45: error: 'pthread_setspecific' was not declared in this scope ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp: In function 'bool OS_FreeTLSIndex(OS_TLSIndex)': ../../../Source/ThirdParty/ANGLE/src/compiler/ossource_posix.cpp:60:34: error: 'pthread_key_delete' was not declared in this scope Link: http://build.webkit.org/builders/Qt%20Windows%2032-bit%20Release/builds/28050/steps/compile-webkit/logs/stdio It seems ANGLE_OS_POSIX isn't defined.
The QT port is no longer part of WebKit.