The autoconf macros AX_COMPILER_FLAGS_{CFLAGS|GIR|LDFLAGS} test
for compiler and linker support of various flags, and add the flags to
the generated output.
If the command-line option '--enable-compile-warnings' is specified to
'configure', a number of additional warning options is also added to the
output. This is the default.
This update requires the presence of the GNU autoconf-archive in the
system.
This patch updates m4/compiler-warnings.m4 as follows to make it more
compatible with clang:
* clang doesn't support -Wunused-but-set-variable, which can be replaced
with -Wunused-variable as the latter covers unused variables with or
without an assigned value and is supported by gcc and clang.
* -Wno-unused-function is added to let clang ignore unused functions that
are auto-generated.
By default the build used -Wno-unused-but-set-variable but that's
clearly not what we want. Fix those problems.
When using clang, the compiler doesn't error on unknown compile
options, so let's add -Werror to the checking too.
CC='clang'
configure:3408: checking for gcc
configure:3435: result: clang
...
configure:17644: checking whether gcc understands -Wno-unused-but-set-variable
configure:17657: clang -c -Wall -std=gnu89 -g -O2 -Wmissing-declarations -Wmissing-prototypes -Wdeclaration-after-statement -Wstrict-prototypes -Wno-unused-parameter -Wno-sign-compare -Wno-deprecated-declarations -Wno-unused-but-set-variable conftest.c >&5
warning: unknown warning option '-Wno-unused-but-set-variable'; did you mean '-Wno-unused-const-variable'? [-Wunknown-warning-option]
1 warning generated.
configure:17657: $? = 0
configure:17666: result: yes
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
It's annoying for distributors to build with -Werror, since it means
that compiler upgrades can break the build. Let's let them disable it,
but keep it enabled by default.
Remove the need to run `gtkdocize' when building from git; this should
be an operation done by the maintainer when modernizing the gtk-doc
setup (think of e.g. gettextize), no need to do it unconditionally.
This makes it easier for platforms without gtk-doc to build from git.
When trying to build with documentation enabled and gtk-doc isn't
found, we get some nice warnings and errors in the configure report:
checking for gtk-doc... no
configure: WARNING:
You will not be able to create source packages with 'make dist'
because gtk-doc >= 1.0 is not found.
checking for gtkdoc-check... no
checking for gtkdoc-check... no
checking for gtkdoc-rebase... no
checking for gtkdoc-mkpdf... no
checking whether to build gtk-doc documentation... yes
configure: error:
You must have gtk-doc >= 1.0 installed to build documentation for
ModemManager. Please install gtk-doc or disable building the
documentation by adding '--disable-gtk-doc' to './configure'.
Files generated with gtkdocize (gtk-doc) 1.25.1.
We now don't break the strict aliasing rules.
Also, having a compiler flag that disables a warning among the flags that are
meant to add extra sanity checking is not correct either:
--enable-extra-warnings=no would generate a bad aliasin warning while
the --enable-extra-warnings=yes would not.
GValueArray is deprecated since GLib 2.31.14, but we need to use it for
dbus-glib based code.
We should re-enable deprecation warnings once we switch to GDBus.
