Simplify condition.
Merge topic 'WriteCompilerDetectionHeader-module' into next

58af1d47 Simplify condition.
Add the WriteCompilerDetectionHeader module.

Provide a function to write a portable header to detect compiler
features.  Generate a preprocessor #error for unknown compilers
and compiler versions whose features are not yet recorded.  This
error condition might be relaxed in the future, but for now it
is useful for verification of expectations.
Merge topic 'WriteCompilerDetectionHeader-module' into next

aba514a6 Add the WriteCompilerDetectionHeader module.