docs: compiling: Add a note about use of CFLAGS for optimization

Meson doesn't interpret what's set in CFLAGS, but rather simply appeds
it to the command line. Thus any logic which is based on the
optimization level will not work.

Note the caveat in the docs and instruct users to use
``--optimization=N`` instead.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/docs/compiling.rst b/docs/compiling.rst
index 800264d2f9cce63f29fb679befe4488ad6425e4a..0a47a50569188a108dfe93a7b9d1c8129125e122 100644 (file)
--- a/docs/compiling.rst
+++ b/docs/compiling.rst
@@ -112,6 +112,11 @@ Please ensure that you have the appropriate minimal ``meson`` version installed
 in your build environment. The minimal version for a specific package can be
 checked in the top level ``meson.build`` file in the ``meson_version`` field.
 
+**DO NOT** use the ``CFLAGS`` environment variable to set optimizations
+(e.g. ``CFLAGS=-O0``), but rather use Meson's ``--optimization=0`` option.
+Certain internal build options are based on the configured optimization value
+and Meson does not interpret ``CFLAGS``.
+
 
 Compiling the sources
 ---------------------