legacy pcre being preferred over pcre2 during ./configure

[Vitadek]

Just to say, this is probably a skill issue, but I've been building this through a Dockerfile:
Docker version 28.5.1, build e180ab8

...
#
# Check for libpcre only if explicitly requested
#
if test "x${with_pcre}" != "x" && test "x${with_pcre}" != "xno"; then
  CHECK_PCRE
else
  #
  # Check for pcre2
  #
  PROG_PCRE2
fi
...

##PCRE
if test "x${with_pcre}" != "x" \
   && test "x${with_pcre}" != "xno" \
   && test "x${PCRE_VERSION}" == "x"; then
    AC_MSG_NOTICE([*** pcre library not found.])
else
    echo "   + PCRE                                          ....found "
    echo "     using pcre v${PCRE_VERSION}"
    echo "      ${PCRE_LDADD}, ${PCRE_CFLAGS}"
fi


## PCRE2
if test "x$PCRE2_FOUND" = "x0"; then
    echo "   + PCRE2                                          ....not found"
fi
if test "x$PCRE2_FOUND" = "x1"; then
    AS_ECHO_N("   + PCRE2                                          ....found ")
    if ! test "x$PCRE2_VERSION" = "x"; then
        echo "v${PCRE2_VERSION}"
    else
        echo ""
    fi
    echo "      ${PCRE2_DISPLAY}"
fi
if test "x$PCRE2_FOUND" = "x2"; then
    echo "   + PCRE2                                          ....disabled"
fi
...

For some reason, during build time, even though pcre is an optional package, it complains that pcre (legacy) is needed during build time. I was able to successfully build this with the trixie:latest docker image by using explicit ./configure flags, but when trying this on alma8/alma9 builds, I get some issues when setting my .spec %configure macro.

...
RUN export PKG_CONFIG_PATH=/usr/lib/x86_64-linux-gnu/pkgconfig && \
    ./configure \                                                                                                                                             
        --prefix=/usr \                                                        
        --libdir=/usr/lib/x86_64-linux-gnu \                                                                                                                  
        --enable-examples=no \
        --disable-debug-logs \
       #### I had to explicitly set the following for it to work ###
        --with-pcre=no \
        --with-pcre2=/usr
...

The following build errors out

...
%configure \
        --prefix=/usr \                                                        
        --libdir=/usr/lib64 \                                                                                                                                 
        --enable-examples=no \
        --disable-debug-logs \    
       #### Same flags ####                                             
        --with-pcre=no \                                                       
        --with-pcre2=/usr
...

12.01 checking for libpcre config script... checking for pcre-config... no                                                                                    
12.01 configure: pcre-config not found in environment. checking known paths                                                                                   
12.01 no                                                                                                                                                      
12.01 configure: *** pcre library not found.                                                                                                                  
12.01 configure: error: pcre library is required                                                                                                              
12.04                                                                                                                                                         
12.04                                                                                                                                                         
12.04 RPM build errors:                                                                                                                                       
12.04 error: Bad exit status from /var/tmp/rpm-tmp.lZBCcV (%build)                                                                                            
12.04     Macro expanded in comment on line 48: %{_libdir} is /usr/lib64                                                                                      
12.04                                                                                                                                                         
12.04     Macro expanded in comment on line 49: %{_includedir} is /usr/include                                                                                
12.04                                                                                                                                                         
12.04     Bad exit status from /var/tmp/rpm-tmp.lZBCcV (%build)

I've tried removing the pcre flags to let the build.sh and autoconf figure things out, and I've tried installing pcre-devel anyways with prcre2-devel and the same issues occur.

Sometimes, configure will pass through to the build stage, but it'll find out that the pcre header files don't exist and chastise me.

EDIT: I guess I set it up with pcre-devel (legacy package) and it worked and identified pcre2 afterwards, but even with explicit ./configure flag it still looks for the pcre-devel package.

[airween]

Hi @Vitadek,

sorry for the late reply.

I think the solution is simple: just leave the --with-pcre=no option, and if your PCRE2 library is in system's default path, you shouldn't pass --with-pcre2=/usr. The build system uses PCRE2, and probably that will find all necessary things.