Revert "The GCC Optimization Levels AGAIN [1/2]"

This reverts commit b2033ed60d602a086f71a217338a5bd052aa10c3.
Revert "Rework if statements for GCC Level. [1/2]"

This reverts commit b510ceafa5cae1006916cbf9aaf57b986450af05.
Revert "Allow defining multiple GCC O Levels 2/2"

This reverts commit f8e5ef22f0ccb37260ef5e8ab31d2d3645f2b3c5.