Specifies the available build types (configurations) on multi-config
generators (e.g. Visual Studio,
Ninja Multi-Config). Typical values
but custom build types can also be defined.
This variable is initialized by the first
enable_language() command called in a project when a new build
tree is first created. If the
environment variable is set, its value is used. Otherwise, the default
value is generator-specific.
Depending on the situation, the values in this variable may be treated case-sensitively or case-insensitively. See Build Configurations for discussion of this and other related topics.
For single-config generators, see