⚙️ Install pip via get-pip.py

Dockerfile-boxed-base

@@ -8,7 +8,9 @@ RUN echo "APT::Acquire::Retries \"3\";" > /etc/apt/apt.conf.d/80-retries && \
     apt-get update && \
     apt-get install -y \
       curl xz-utils \
-      python3-pip \
+      build-essential python3-dev \
+# For get-pip.py:
+      python3-distutils \
 # For add-apt-repository:
       software-properties-common \
 # XML utils
@@ -23,11 +25,17 @@ RUN echo "APT::Acquire::Retries \"3\";" > /etc/apt/apt.conf.d/80-retries && \
 COPY ocrd_logging.py /etc/
 
 
-# Build pip installable stuff
-RUN pip3 install --no-cache-dir --upgrade pip && \
-    pip3 install --no-cache-dir \
-# Resolve conflicts early:
-        'setuptools >= 41.0.0' \
+# Install pip (and setuptools)
+# We use get-pip.py here to avoid
+# a. having to upgrade from Ubuntu's pip
+# b. the dreaded "old script wrapper" error message
+RUN curl -sSL https://bootstrap.pypa.io/get-pip.py -o get-pip.py && \
+    python3 get-pip.py && \
+    rm -f get-pip.py
+
+
+# Install pip installable-stuff
+RUN pip3 install --no-cache-dir \
         'ocrd >= 2.13.1'