If the C bootstrap compiler builds on a 64 bit host (x86-64) but Imp programs
don't build, you may need to install the 32-bit libraries, with something like:

   sudo apt-get install gcc-multilib

I was able to build on my home 32/64 linux (x86), but my web host's linux fails with
the errors appended after the ####, and unfortunately users do not have permission to
install new code on that machine so that's the limit of my testing.

===

Imp77 is invoked here using the script 'imp2021-c' which calls pass1, pass2, and pass3elf;
and if successful (and -c is not given) will link to an x86 executable.

HOWEVER the exact options for gcc depend somewhat on how exactly gcc has been installed.
If your Imp compilation fails at the linking stage, edit imp202-c and modify it until
you can link 32 bit programs successfully.

===

Note that this bootstrap compiler does *not* install/modify the ld.i77.script
file recommended at https://github.com/siliconsam/imp2021/tree/main/build/imp-linux
and it seems to work just fine.

Frankly I don't understand the instructions below, it's not at all clear what
exactly goes in the file and precisely where it goes.  We need something like
a bash+ecce script to apply the mod automatically.

Does "SECTION" go in the file?
Does "INSERT BEFORE .data" go in the file or is that an instruction?
Does the whole bracketed group of four lines go before the .data line,
or just the 2 lines in the brackets?:

  {
    . = ALIGN(32);
    ITRAP : { *(ITRAP$B) *(ITRAP$D) *(ITRAP$F) }
  }
                
+--------------------------------------------------------------------------------------+
|  The loader script "ld.i77.script" in "imp-linux/compiler" assumes                   |
|  that ld will concatenate this script into the default GCC loader script.            |
|  This ld.i77.script is ESSENTIAL.                                                    |
|  If not then                                                                         |
|  * run "ld --verbose"                                                                |
|  * copy the generated ld script into a file "compiler/ld.script"                     |
|  * insert the "section" contents of ld.i77.script before the .data                   |
|  instructions into the "compiler/ld.script"                                          |
|  * rename the "compiler/ld.script" to be "compiler/ld.i77.script"                    |
|  This potential amendment to ld.i77.script MUST be done BEFORE running               |
|  the "make bootstrap" in the compiler folder                                         |
|                                                                                      |
|  Imp-77 event handling depends on the individual event traps being in                |
|  one section "ITRAP" in the order of ITRAP$B, all ITRAP$D the ITRAP$F sections.      |
|  The Windows linker does this automatically, but the GCC loader ld needs to be told! |
+--------------------------------------------------------------------------------------+


######################################################


It works on my home x86 system:

  Distributor ID: Ubuntu
     Description: Ubuntu 18.04.6 LTS
         Release: 18.04
        Codename: bionic
         Chassis: desktop
Operating System: Ubuntu 18.04.6 LTS
          Kernel: Linux 4.15.0-159-generic
    Architecture: x86

arch reports i686


But below are the errors from running on this x86-64 system:

  Distributor ID: Ubuntu
     Description: Ubuntu 18.04.4 LTS
         Release: 18.04
        Codename: bionic
         Chassis: server
Operating System: Ubuntu 18.04.4 LTS
          Kernel: Linux 4.14.117-grsec-grsec+
    Architecture: x86-64

arch reports x86_64


goodlife:~/tmp/imptest> ./imp2021-c hellow.imp
    4 Statements compiled
    C executable post-execution checksum 3624383233
    Code 50 bytes  Data 102 bytes  Diag 32 bytes  Total size 184 bytes
    Generated for IMP source file: '/home/gtoal/tmp/imptest/hellow-c.imp'

/usr/bin/ld: cannot find Scrt1.o: No such file or directory
/usr/bin/ld: cannot find crti.o: No such file or directory
/usr/bin/ld: skipping incompatible //usr/lib/x86_64-linux-gnu/libm.so when searching for -lm
/usr/bin/ld: skipping incompatible //usr/lib/x86_64-linux-gnu/libm.a when searching for -lm
/usr/bin/ld: cannot find -lm
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/7/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/7/libgcc_s.so.1 when searching for libgcc_s.so.1
/usr/bin/ld: cannot find libgcc_s.so.1
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/7/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
collect2: error: ld returned 1 exit status