To make ANSILib, RISCOSLib, stubs and Shared C library module compatible with
26-bit RISC OS 3.1 onwards (including APCS-32 client support in Shared C
Library), build with APCS = APCS-R, No26bitCode = {FALSE}, No32bitCode =
{TRUE}.

To make RISCOSLib, stubs compatible with 26 or 32-bit RISC OS 3.1 onwards,
build with APCS = APCS-32. The resulting programs will require an APCS-32 capable
Shared C Library.

To make ANSILib compatible with 26 or 32-bit RISC OS 3.5 onwards, build with
APCS = APCS-32, No26bitCode = {TRUE}, No32bitCode = {FALSE}.

To make Shared C Library compatible with 32-bit RISC OS, build with APCS = APCS-32.

An APCS-32 Shared C Library will NOT run 26-bit programs, even on a 26-bit
system; an APCS-R Shared C Library must be used. In a build using APCS-32,
the SCL must be forced to APCS-R - pass the option SCL_APCS="-APCS 3/26bit"
in the components file to acheive this.