Remove unneeded compiler flags. Increase size for -Wlarger-than to 2M…

…. Add flags for Debug builds and edit flags for Asan builds in documentation.

configure.ac

@@ -21,7 +21,6 @@ CFLAGS="$CFLAGS \
 	-fPIC \
 	-fstack-protector-all \
 	-fstrict-aliasing \
-	-ggdb3 \
 	-pthread \
 	-Wall \
 	-Warray-bounds \
@@ -30,7 +29,7 @@ CFLAGS="$CFLAGS \
 	-Wformat-security \
 	-Wformat=2 \
 	-Winit-self \
-	-Wlarger-than=65537 \
+	-Wlarger-than=2097152 \
 	-Wmissing-declarations \
 	-Wmissing-format-attribute \
 	-Wmissing-include-dirs \
@@ -53,7 +52,6 @@ case "$CC" in
 *clang*)
 	# Specific clang flags
 	CFLAGS="$CFLAGS \
-		-Wno-cast-align \
 		-Wno-initializer-overrides \
 		-Wno-missing-noreturn"
 ;;
@@ -65,7 +63,6 @@ cc*)
 *)
 	# Specific gcc flags
 	CFLAGS="$CFLAGS \
-		-Wcast-align \
 		-Wno-override-init \
 		-Wunsafe-loop-optimizations \
 		-Wunused-but-set-variable"

src/mainpage.dox

@@ -3111,6 +3111,15 @@ sudo supervisorctl update
  * bugs and the like, as it can provide information about the values of
  * variables when they were used and the application crashed.
  *
+ * First of all make sure that debugging symbols are enabled by reconfiguring Janus like this:
+ *
+ \verbatim
+CFLAGS="-Og -g3 -ggdb3 -fno-omit-frame-pointer" ./configure --prefix=/opt/janus
+ \endverbatim
+ *
+ * Once done configuring, do a \c make \c clean (to make sure
+ * everything is recompiled from scratch) and then a \c make and \c make \c install.
+ *
  * When Janus crashes, you should get a core dump file somewhere. This is
  * a recorded state of the application memory at the time of crashing, and
  * so a backtrace of what lead to an issue can help. You can open such
@@ -3145,7 +3154,7 @@ gdb bt
  * Once you've installed libasan, reconfigure Janus like this:
  *
  \verbatim
-CFLAGS="-O1 -g3 -ggdb3 -fno-omit-frame-pointer -fsanitize=address -fno-sanitize-recover=all -fsanitize-address-use-after-scope" LDFLAGS="-fsanitize=address" ./configure --prefix=/opt/janus
+CFLAGS="-O0 -g3 -ggdb3 -fno-omit-frame-pointer -fno-optimize-sibling-calls -fsanitize=address -fsanitize-address-use-after-scope -fno-sanitize-recover=all" LDFLAGS="-fsanitize=address" ./configure --prefix=/opt/janus
  \endverbatim
  *
  * Of course you're free to add whatever additional configuration parameter