It seems there are 4 main options for Amiga C compilers

• Sas/C
  • The one that is recommended most
  • Found it on http://www.theisozone.com/downloads/retro/amiga/sasc-c-development-system-v658-for-amiga-with-manuals/
    Update: Ok - that link went stale - I put the archive
    here on SASC-6.0-6.5.zip
  • it works :)
  • It's not cli based though ... (is it?) and it seems you need to write some custom make-type file? I found it to be a bit hard to wrap my head around.
  • I don't like it, maybe it's me ...
  • Update: oh, you can also just use it from the command line - yes - seems to work ok.  let's compare the output with gcc.
• VBCC
  • made for cross platform compiling
  • needs addiotional header files from os3.9 NDK
  • it appears much easier to set this up outside the amiga using https://github.com/kusma/amiga-dev
  • works ... if I ever want to compile on windows this seems a good way.
• Storm C
  • a full IDE - not really needed
  • V4 is still being sold here
  • Found V3 on http://www.amigafuture.de/downloads.php?view=detail&df_id=664 but could not get it to work
    • Ah ... the name of the install script is wrong (correct it in Install_storm_hd_english.info)
      
      
      
    • And the install script refers to the folder "StormC_3.0" instead of "StormC_3_0" ->rename it
    • Ok - it installs now.
    • Works: Simple Hello-word compiles and runs - Yay!
    • I like it. It seems to be the only mature C IDE on the Amiga?
    • emeraldX11 code barfs though ... to investigate.
• GCC
  • the latest standalone version on aminet is 2.70, seems a bit old.
  • This package is promising: http://aminet.net/package/dev/gcc/ADE
    • Yes, this seems the one ... based on gcc 2.95
    • I like that you can just park it somwhere, run 1 "ADE-Startup" scriopt and everything works, nothing to install, nothing to configure.
    • I seems to compile the sources I used for my emscripten port nicely - ACE! Got myself a working Amiga binary.
  • Gcc 6.2 was ported back to 68k atari: http://d-bug.mooo.com/beyondbrown/post/gcc-6/ - cool!
  • also very cool ,to check out if I ever take on Assembler: online C to assembler tool: http://brownbot.hopto.org/

After some fiddling I decided to go with GCC 2.95 on the amiga.
Would there be any performance differences in the final binary when using different compilers? To test.

Update:

• It appears Sas/C produces much smaller binaries than GCC
• to autogenerate the smakefile use "mkmk" in the sourcedir
• to build the smakefile use "smake"
• bottom line: I like Sas/C - let's go with that.

Update2:

After some time I forgot how to get a SAS/C environment up and running when you start with a fresh Amiga system, so here's a reminder for myself.
SAS/C needs some assigns:

• SC: - The main installation folder and assign containing the programs, libraries, headers and sample code.
• SC:C - The compiler program files (added to path)
• LIB: - The SAS/C and Amiga link library files
• INCLUDE: - The C compiler and amiga NDUK header files
• CXXINCLUDE: - The C++ compiler header files

In my case that adds to

ASSIGN SC: DH1:sc
ASSIGN LIB: DH1:sc/lib
ASSIGN INCLUDE: DH1:sc/include
ASSIGN CXXINCLUDE: DH1:sc/cxxinclude
PATH DH1:sc/c ADD

then use mkmk to generate a smakefile and smake to compile it