Xcode Build Variables List. Adopted from: http://stackoverflow.com/questions/6910901/canonical-list-of-xcode-environment-variables

gistfile1.txt

ACTION
AD_HOC_CODE_SIGNING_ALLOWED
ALTERNATE_GROUP
ALTERNATE_MODE
ALTERNATE_OWNER
ALWAYS_SEARCH_USER_PATHS
ALWAYS_USE_SEPARATE_HEADERMAPS
APPLE_INTERNAL_DEVELOPER_DIR
APPLE_INTERNAL_DIR
APPLE_INTERNAL_DOCUMENTATION_DIR
APPLE_INTERNAL_LIBRARY_DIR
APPLE_INTERNAL_TOOLS
APPLY_RULES_IN_COPY_FILES
ARCHIVE_DSYMS_PATH
ARCHIVE_PATH
ARCHIVE_PRODUCTS_PATH
ARCHS
ARCHS_STANDARD
ARCHS_STANDARD_32_64_BIT
ARCHS_STANDARD_32_BIT
ARCHS_STANDARD_64_BIT
ARCHS_STANDARD_INCLUDING_64_BIT
ARCHS_UNIVERSAL_IPHONE_OS
ASSETCATALOG_COMPILER_APPICON_NAME
ASSETCATALOG_COMPILER_LAUNCHIMAGE_NAME
AVAILABLE_PLATFORMS
BUILD_COMPONENTS
BUILD_DIR
BUILD_ROOT
BUILD_STYLE
BUILD_VARIANTS
BUILT_PRODUCTS_DIR
CACHE_ROOT
CCHROOT
CHMOD
CHOWN
CLANG_ENABLE_OBJC_ARC
CLANG_WARN_CONSTANT_CONVERSION
CLANG_WARN_ENUM_CONVERSION
CLANG_WARN_INT_CONVERSION
CLANG_WARN__DUPLICATE_METHOD_MATCH
CLASS_FILE_DIR
CLEAN_PRECOMPS
CLONE_HEADERS
CODESIGNING_FOLDER_PATH
CODE_SIGNING_ALLOWED
CODE_SIGNING_REQUIRED
CODE_SIGN_CONTEXT_CLASS
CODE_SIGN_IDENTITY
CODE_SIGN_STYLE
COLOR_DIAGNOSTICS
COMBINE_HIDPI_IMAGES
COMPOSITE_SDK_DIRS
COMPRESS_PNG_FILES
CONFIGURATION
CONFIGURATION_BUILD_DIR
CONFIGURATION_TEMP_DIR
CONTENTS_FOLDER_PATH
COPYING_PRESERVES_HFS_DATA
COPY_PHASE_STRIP
COPY_RESOURCES_FROM_STATIC_FRAMEWORKS
CP
CREATE_INFOPLIST_SECTION_IN_BINARY
CURRENT_ARCH
CURRENT_PROJECT_VERSION
CURRENT_VARIANT
DEAD_CODE_STRIPPING
DEBUGGING_SYMBOLS
DEBUG_INFORMATION_FORMAT
DEFAULT_COMPILER
DEFAULT_KEXT_INSTALL_PATH
DEPLOYMENT_LOCATION
DEPLOYMENT_POSTPROCESSING
DERIVED_FILES_DIR
DERIVED_FILE_DIR
DERIVED_SOURCES_DIR
DEVELOPER_APPLICATIONS_DIR
DEVELOPER_BIN_DIR
DEVELOPER_DIR
DEVELOPER_FRAMEWORKS_DIR
DEVELOPER_FRAMEWORKS_DIR_QUOTED
DEVELOPER_LIBRARY_DIR
DEVELOPER_SDK_DIR
DEVELOPER_TOOLS_DIR
DEVELOPER_USR_DIR
DEVELOPMENT_LANGUAGE
DEVELOPMENT_TEAM
DOCUMENTATION_FOLDER_PATH
DO_HEADER_SCANNING_IN_JAM
DSTROOT
DT_TOOLCHAIN_DIR
DWARF_DSYM_FILE_NAME
DWARF_DSYM_FILE_SHOULD_ACCOMPANY_PRODUCT
DWARF_DSYM_FOLDER_PATH
EFFECTIVE_PLATFORM_NAME
EMBEDDED_PROFILE_NAME
ENABLE_HEADER_DEPENDENCIES
ENTITLEMENTS_ALLOWED
ENTITLEMENTS_REQUIRED
EXCLUDED_INSTALLSRC_SUBDIRECTORY_PATTERNS
EXCLUDED_RECURSIVE_SEARCH_PATH_SUBDIRECTORIES
EXECUTABLES_FOLDER_PATH
EXECUTABLE_FOLDER_PATH
EXECUTABLE_NAME
EXECUTABLE_PATH
FILE_LIST
FIXED_FILES_DIR
FRAMEWORKS_FOLDER_PATH
FRAMEWORK_FLAG_PREFIX
FRAMEWORK_SEARCH_PATHS
FRAMEWORK_VERSION
FULL_PRODUCT_NAME
GCC3_VERSION
GCC_C_LANGUAGE_STANDARD
GCC_INLINES_ARE_PRIVATE_EXTERN
GCC_PFE_FILE_C_DIALECTS
GCC_PRECOMPILE_PREFIX_HEADER
GCC_PREFIX_HEADER
GCC_PREPROCESSOR_DEFINITIONS
GCC_SYMBOLS_PRIVATE_EXTERN
GCC_THUMB_SUPPORT
GCC_TREAT_WARNINGS_AS_ERRORS
GCC_VERSION
GCC_VERSION_IDENTIFIER
GCC_WARN_ABOUT_RETURN_TYPE
GCC_WARN_UNINITIALIZED_AUTOS
GCC_WARN_UNUSED_VARIABLE
GENERATE_MASTER_OBJECT_FILE
GENERATE_PKGINFO_FILE
GENERATE_PROFILING_CODE
GID
GROUP
HEADERMAP_INCLUDES_FLAT_ENTRIES_FOR_TARGET_BEING_BUILT
HEADERMAP_INCLUDES_FRAMEWORK_ENTRIES_FOR_ALL_PRODUCT_TYPES
HEADERMAP_INCLUDES_NONPUBLIC_NONPRIVATE_HEADERS
HEADERMAP_INCLUDES_PROJECT_HEADERS
HEADER_SEARCH_PATHS
ICONV
INFOPLIST_EXPAND_BUILD_SETTINGS
INFOPLIST_FILE
INFOPLIST_OUTPUT_FORMAT
INFOPLIST_PATH
INFOPLIST_PREPROCESS
INFOSTRINGS_PATH
INSTALL_DIR
INSTALL_GROUP
INSTALL_MODE_FLAG
INSTALL_OWNER
INSTALL_PATH
INSTALL_ROOT
IPHONEOS_DEPLOYMENT_TARGET
JAVAC_DEFAULT_FLAGS
JAVA_APP_STUB
JAVA_ARCHIVE_CLASSES
JAVA_ARCHIVE_TYPE
JAVA_COMPILER
JAVA_FOLDER_PATH
JAVA_FRAMEWORK_RESOURCES_DIRS
JAVA_JAR_FLAGS
JAVA_SOURCE_SUBDIR
JAVA_USE_DEPENDENCIES
JAVA_ZIP_FLAGS
JIKES_DEFAULT_FLAGS
KEEP_PRIVATE_EXTERNS
LD_DEPENDENCY_INFO_FILE
LD_GENERATE_MAP_FILE
LD_MAP_FILE_PATH
LD_NO_PIE
LD_QUOTE_LINKER_ARGUMENTS_FOR_COMPILER_DRIVER
LEGACY_DEVELOPER_DIR
LEX
LIBRARY_FLAG_NOSPACE
LIBRARY_FLAG_PREFIX
LIBRARY_KEXT_INSTALL_PATH
LIBRARY_SEARCH_PATHS
LINKER_DISPLAYS_MANGLED_NAMES
LINK_FILE_LIST_normal_armv7
LINK_FILE_LIST_normal_armv7s
LINK_WITH_STANDARD_LIBRARIES
LOCALIZED_RESOURCES_FOLDER_PATH
LOCAL_ADMIN_APPS_DIR
LOCAL_APPS_DIR
LOCAL_DEVELOPER_DIR
LOCAL_LIBRARY_DIR
MACH_O_TYPE
MAC_OS_X_PRODUCT_BUILD_VERSION
MAC_OS_X_VERSION_ACTUAL
MAC_OS_X_VERSION_MAJOR
MAC_OS_X_VERSION_MINOR
MARKETING_VERSION
MODULE_CACHE_DIR
NATIVE_ARCH
NATIVE_ARCH_32_BIT
NATIVE_ARCH_64_BIT
NATIVE_ARCH_ACTUAL
NO_COMMON
OBJECT_FILE_DIR
OBJECT_FILE_DIR_normal
OBJROOT
ONLY_ACTIVE_ARCH
OPTIMIZATION_LEVEL
OS
OSAC
OTHER_CFLAGS
OTHER_CPLUSPLUSFLAGS
OTHER_LDFLAGS
PACKAGE_TYPE
PASCAL_STRINGS
PATH
PATH_PREFIXES_EXCLUDED_FROM_HEADER_DEPENDENCIES
PBDEVELOPMENTPLIST_PATH
PFE_FILE_C_DIALECTS
PKGINFO_FILE_PATH
PKGINFO_PATH
PLATFORM_DEVELOPER_APPLICATIONS_DIR
PLATFORM_DEVELOPER_BIN_DIR
PLATFORM_DEVELOPER_LIBRARY_DIR
PLATFORM_DEVELOPER_SDK_DIR
PLATFORM_DEVELOPER_TOOLS_DIR
PLATFORM_DEVELOPER_USR_DIR
PLATFORM_DIR
PLATFORM_NAME
PLATFORM_PREFERRED_ARCH
PLATFORM_PRODUCT_BUILD_VERSION
PLIST_FILE_OUTPUT_FORMAT
PLUGINS_FOLDER_PATH
PRECOMPS_INCLUDE_HEADERS_FROM_BUILT_PRODUCTS_DIR
PRECOMP_DESTINATION_DIR
PRESERVE_DEAD_CODE_INITS_AND_TERMS
PRIVATE_HEADERS_FOLDER_PATH
PRODUCT_BUNDLE_IDENTIFIER
PRODUCT_NAME
PRODUCT_SETTINGS_PATH
PRODUCT_TYPE
PROFILING_CODE
PROJECT
PROJECT_DERIVED_FILE_DIR
PROJECT_DIR
PROJECT_FILE_PATH
PROJECT_NAME
PROJECT_TEMP_DIR
PROJECT_TEMP_ROOT
PROVISONING_PROFILE_SPECIFIER
PROVISIONING_PROFILE_REQUIRED
PUBLIC_HEADERS_FOLDER_PATH
RECURSIVE_SEARCH_PATHS_FOLLOW_SYMLINKS
REMOVE_CVS_FROM_RESOURCES
REMOVE_GIT_FROM_RESOURCES
REMOVE_HG_FROM_RESOURCES
REMOVE_SVN_FROM_RESOURCES
RESOURCE_RULES_REQUIRED
REZ_COLLECTOR_DIR
REZ_OBJECTS_DIR
SCAN_ALL_SOURCE_FILES_FOR_INCLUDES
SCRIPTS_FOLDER_PATH
SDKROOT
SDK_DIR
SDK_NAME
SDK_PRODUCT_BUILD_VERSION
SED
SEPARATE_STRIP
SEPARATE_SYMBOL_EDIT
SET_DIR_MODE_OWNER_GROUP
SET_FILE_MODE_OWNER_GROUP
SHALLOW_BUNDLE = YES
SHARED_DERIVED_FILE_DIR
SHARED_FRAMEWORKS_FOLDER_PATH
SHARED_PRECOMPS_DIR
SHARED_SUPPORT_FOLDER_PATH
SKIP_INSTALL
SOURCE_ROOT
SRCROOT
STRINGS_FILE_OUTPUT_ENCODING
STRIP_INSTALLED_PRODUCT
STRIP_STYLE
SUPPORTED_DEVICE_FAMILIES
SUPPORTED_PLATFORMS
SYMROOT
SYSTEM_ADMIN_APPS_DIR
SYSTEM_APPS_DIR
SYSTEM_CORE_SERVICES_DIR
SYSTEM_DEMOS_DIR
SYSTEM_DEVELOPER_APPS_DIR
SYSTEM_DEVELOPER_BIN_DIR
SYSTEM_DEVELOPER_DEMOS_DIR
SYSTEM_DEVELOPER_DIR
SYSTEM_DEVELOPER_DOC_DIR
SYSTEM_DEVELOPER_GRAPHICS_TOOLS_DIR
SYSTEM_DEVELOPER_JAVA_TOOLS_DIR
SYSTEM_DEVELOPER_PERFORMANCE_TOOLS_DIR
SYSTEM_DEVELOPER_RELEASENOTES_DIR
SYSTEM_DEVELOPER_TOOLS
SYSTEM_DEVELOPER_TOOLS_DOC_DIR
SYSTEM_DEVELOPER_TOOLS_RELEASENOTES_DIR
SYSTEM_DEVELOPER_USR_DIR
SYSTEM_DEVELOPER_UTILITIES_DIR
SYSTEM_DOCUMENTATION_DIR
SYSTEM_KEXT_INSTALL_PATH
SYSTEM_LIBRARY_DIR
TARGETED_DEVICE_FAMILY
TARGETNAME
TARGET_BUILD_DIR
TARGET_DEVICE_PLATFORM_NAME
TARGET_NAME
TARGET_TEMP_DIR
TEMP_DIR
TEMP_FILES_DIR
TEMP_FILE_DIR
TEMP_ROOT
TOOLCHAINS
UID
UNLOCALIZED_RESOURCES_FOLDER_PATH
UNSTRIPPED_PRODUCT
USER
USER_APPS_DIR
USER_LIBRARY_DIR
USE_DYNAMIC_NO_PIC
USE_HEADERMAP
USE_HEADER_SYMLINKS
VALIDATE_PRODUCT
VALID_ARCHS
VERBOSE_PBXCP
VERSIONPLIST_PATH
VERSION_INFO_BUILDER
VERSION_INFO_FILE
VERSION_INFO_STRING
WRAPPER_EXTENSION
WRAPPER_NAME
WRAPPER_SUFFIX
XCODE_APP_SUPPORT_DIR
XCODE_PRODUCT_BUILD_VERSION
XCODE_VERSION_ACTUAL
XCODE_VERSION_MAJOR
XCODE_VERSION_MINOR
XPCSERVICES_FOLDER_PATH
YACC
arch
diagnostic_message_length
variant

TARGET_DEVICE_PLATFORM_NAME

can be macosx, iphone, or iphonesimulator

TZ

Example:
key: TZ, value: MSK
Description:
allows you to hardcode time zone of your application. Could be useful when you have developers from different time zones and you have tests that can fail due to time zone.