"' @bmk"-pragma ignored in application main source file

[GWRon]

SuperStrict

' @bmk echo *** Building my cool app ***
' @bmk addccopt -DSPECIAL_OPTION
print "hello"

Compiling this code leads to about the following (added some "prints:

Building untitled1
Loading /BlitzMaxNG/bin/custom.bmk
TBMKGlobals.AddOption: variable=ld_opts key=static-stdc value=-static-libstdc++
MakeApp() called
->   globals.Get(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 
->   source.cc_opts = 
....
TModOpt.addOption: qval=Authors: Mark Sibly, Simon Armstrong
....
TModOpt.addOption: qval=CC_OPTS: -DGC_THREADS -D_REENTRANT -DPARALLEL_MARK -DATOMIC_UNCOLLECTABLE -DLARGE_CONFIG -DUSE_MMAP -DUSE_MUNMAP -DMUNMAP_THRESHOLD=3

[ 23%] Processing:untitled1.bmx
*** Building my cool app ***
arg1: -DSPECIAL_OPTION
TBMKGlobals.AddOption: variable=cc_opts key=-DSPECIAL_OPTION value=
/BlitzMaxNG/bin/bcc  -g x64 -v -h -s -w -t gui -p linux -o ...
...
[ 85%] Compiling:untitled1.bmx.gui.debug.linux.x64.c
gcc -I/BlitzMaxNG/mod -I/BlitzMaxNG/mod/brl.mod/blitz.mod ...
[100%] Linking:untitled1.debug
g++ -m64 -no-pie -fpie -pthread -o /BlitzMaxNG/tmp/untitled1.debug ...
Executing:untitled1.debug

this looks like the cc_opt of the main file is not used for compiling the mainfile.

[GWRon]

I appended some further debug prints:
changes the output of:

	Method DoBuild(makelib:Int, app_build:Int = False)
...
					Select m.stage
...
						Case STAGE_OBJECT
...
							If processor.BCCVersion() <> "BlitzMax" Then
...
									print "m.cc_opts = " + m.cc_opts
									print "  cc_opts = " + cc_opts
									print "  processor.Option(cc_opts) = " + processor.Option("cc_opts", "")
									print "  globals.Option(cc_opts) = " + globals.Get("cc_opts")

Changing the line from
' @bmk addccopt -DSPECIAL_OPTION to
' @bmk addccopt mykey -DSPECIAL_OPTION

leads to "-DSPECIAL_OPTION" being listed for the "globals" (but not in "[m.]cc_opts")

old:

[ 85%] Compiling:untitled1.bmx.gui.debug.linux.x64.c
m.cc_opts = 
  cc_opts = 
  processor.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3
  globals.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 

new:

[ 85%] Compiling:untitled1.bmx.gui.debug.linux.x64.c
m.cc_opts = 
  cc_opts = 
  processor.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION 
  globals.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION 

[GWRon]

Placing a "pre.bmk" next to my untitled1.bmx (aka unsaved file in maxide):

addccopt mykey -DSPECIAL_OPTION23

results in

Building untitled1
Loading /BlitzMaxNG/bin/custom.bmk
TBMKGlobals.AddOption: variable=ld_opts key=static-stdc value=-static-libstdc++
Loading /BlitzMaxNG/tmp/pre.bmk
arg1: mykey
TBMKGlobals.AddOption: variable=cc_opts key=mykey value=-DSPECIAL_OPTION23
globals.Get(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION23 
processor.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION23 
source.cc_opts = 

[ 85%] Compiling:untitled1.bmx.gui.debug.linux.x64.c
m.cc_opts = 
  cc_opts = 
  processor.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION23  
  globals.Option(cc_opts) =  -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION23  
gcc -IBlitzMaxNG/mod 
	-IBlitzMaxNG/mod/brl.mod/blitz.mod 
	-IBlitzMaxNG/mod/brl.mod/appstub.mod 
	...
	-w -DBMX_NG -fno-strict-aliasing -fpie -fno-exceptions -c -O3 -msse3 -DSPECIAL_OPTION23
	-g -o BlitzMaxNG/tmp/.bmx/untitled1.bmx.gui.debug.linux.x64.o BlitzMaxNG/tmp/.bmx/untitled1.bmx.gui.debug.linux.x64.c


Executing:untitled1.debug
/BlitzMaxNG/tmp/untitled1.debug
hello

Process complete

So this step works (but also requires a "key"). The "key" information is missing in the docs:
https://blitzmax.org/docs/en/language/pre_post_compilation_scripts/