-# Only build the C compiler for stage1, because that is the only one that
-# we can guarantee will build with the native compiler, and also it is the
-# only thing useful for building stage2. STAGE1_CFLAGS (via CFLAGS),
-# MAKEINFO and MAKEINFOFLAGS are explicitly passed here to make them
-# overrideable (for a bootstrap build stage1 also builds gcc.info).
+CREATE_GCOV = create_gcov
+
+TFLAGS =
+
+# Defaults for all stages; some are overridden below.
+
+STAGE_CFLAGS = $(BOOT_CFLAGS)
+STAGE_TFLAGS = $(TFLAGS)
+STAGE_CONFIGURE_FLAGS=@stage2_werror_flag@
+
+[+ FOR bootstrap-stage +]
+# Defaults for stage [+id+]; some are overridden below.
+STAGE[+id+]_CFLAGS = $(STAGE_CFLAGS)
+STAGE[+id+]_CXXFLAGS = $(CXXFLAGS)
+@if target-libstdc++-v3-bootstrap
+# Override the above if we're bootstrapping C++.
+STAGE[+id+]_CXXFLAGS = $(STAGE[+id+]_CFLAGS)
+@endif target-libstdc++-v3-bootstrap
+STAGE[+id+]_TFLAGS = $(STAGE_TFLAGS)
+STAGE[+id+]_CONFIGURE_FLAGS = $(STAGE_CONFIGURE_FLAGS)
+[+ ENDFOR bootstrap-stage +]
+
+# By default, C and C++ are the only stage1 languages, because they are the
+# only ones we require to build with the bootstrap compiler, and also the
+# only ones useful for building stage2.
+
+STAGE1_CFLAGS = @stage1_cflags@
+STAGE1_CHECKING = @stage1_checking@
+STAGE1_LANGUAGES = @stage1_languages@
+# * We force-disable intermodule optimizations, even if
+# --enable-intermodule was passed, since the installed compiler
+# probably can't handle them. Luckily, autoconf always respects
+# the last argument when conflicting --enable arguments are passed.
+# * Likewise, we force-disable coverage flags, since the installed
+# compiler probably has never heard of them.
+# * We also disable -Wformat, since older GCCs don't understand newer %s.
+STAGE1_CONFIGURE_FLAGS = --disable-intermodule $(STAGE1_CHECKING) \
+ --disable-coverage --enable-languages="$(STAGE1_LANGUAGES)" \
+ --disable-build-format-warnings