Use brew --prefix to locate LMDB, OpenSSL, and pcre

This is a temporary fix (see CFE-4385)

Ticket: CFE-4385
Changelog: None
Signed-off-by: Lars Erik Wik <lars.erik.wik@northern.tech>

.github/workflows/macos_unit_tests.yml

@@ -18,7 +18,11 @@ jobs:
     - name: Check tools versions
       run: libtool -V && automake --version && autoconf --version
     - name: Run autotools / configure
-      run: PATH="/opt/homebrew/opt/libtool/libexec/gnubin:$PATH" ./autogen.sh --enable-debug
+      run: >
+        LDFLAGS="-L`brew --prefix lmdb`/lib -L`brew --prefix openssl`/lib -L`brew --prefix pcre2`/lib"
+        CPPFLAGS="-I`brew --prefix lmdb`/include -I`brew --prefix openssl`/include -I`brew --prefix pcre2`/include"
+        PATH="/opt/homebrew/opt/libtool/libexec/gnubin:$PATH"
+        ./autogen.sh --enable-debug
     - name: Compile and link
       run: make -j8 CFLAGS="-Werror -Wall"
     - name: Run unit tests