contrib: fix check-deps.sh to check for weak symbols

Fix check-deps.sh to check for weak symbols so it can detect when an exported
template function is used from another library.

In a previous version of this commit, this change caused an invalid dependency
in the consensus library on the TryParseHex template function from the util
library to be detected, and a suppression was added here. But bitcoin#30377 removed
the invalid dependency so the suppression is no longer needed.

The invalid dependency and problem detecting weak symbol usage was originally
reported by Hennadii Stepanov in
bitcoin#29015 (comment)

contrib/devtools/check-deps.sh

@@ -75,7 +75,7 @@ extract_symbols() {
     local temp_dir="$1"
     for lib in "${!LIBS[@]}"; do
         for lib_path in ${LIBS[$lib]}; do
-            nm -o "$lib_path" | grep ' T ' | awk '{print $3, $1}' >> "${temp_dir}/${lib}_exports.txt"
+            nm -o "$lib_path" | grep ' T \| W ' | awk '{print $3, $1}' >> "${temp_dir}/${lib}_exports.txt"
             nm -o "$lib_path" | grep ' U ' | awk '{print $3, $1}' >> "${temp_dir}/${lib}_imports.txt"
             awk '{print $1}' "${temp_dir}/${lib}_exports.txt" | sort -u > "${temp_dir}/${lib}_exported_symbols.txt"
             awk '{print $1}' "${temp_dir}/${lib}_imports.txt" | sort -u > "${temp_dir}/${lib}_imported_symbols.txt"