fix: use extern mutex and COPT -fPIE -Wno-error. Add Dockerfile

Dockerfile

@@ -5,14 +5,15 @@ RUN apt-get update && \
     useradd -m -d /home/guinness -s /bin/false -r guinness
 
 FROM guinnessd-base
-COPY . /home/guinness
+COPY . /home/guinness/src
 WORKDIR /home/guinness
-RUN make && \
-    mv /home/guinness/guinnessd /usr/local/bin && \
+RUN make -C /home/guinness/src && \
+    mv /home/guinness/src/guinnessd /usr/local/bin && \
+    mv /home/guinness/src/picoles  /usr/local/share && \
     chmod +x /usr/local/bin/guinnessd && \
-    rm -Rf  /home/guinness/* && \
+    rm -Rf  /home/guinness/src && \
     apt-get remove -y make gcc && \
     apt-get autoremove -y
-    
+