Fix build for less common build directories names

Fix build for less common build directories names

scripts/tracetool generates a C preprocessor macro from the name of the
build directory. Any characters which are possible in a directory name
but not allowed in a macro name must be substituted, otherwise builds
will fail.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>