Fix bug (introduced a few commits ago) when generating SFC actions that are mapped onto variables --> Make generate_sfcdecl_c stateless (i.e. does not depend on order by which it is called).
################
# IL operators #
################
# which are not simultaneously
# - keywords (AND, OR, NOT, MOD, XOR),
# - or standard funtion name (which by implication are also keywords)
# (AND, OR, NOT, MOD, XOR, as well as, GE, GT, LE, LT, EQ, NE, SUB, ADD, MUL, DIV)
# - or standard function block name (which by implication are also keywords)
# - invalid identifier name (&, &N)
ANDN
CAL
CALC
CALCN
CD
CLK
CU
IN
JMP
JMPC
JMPCN
LD
LDN
ORN
PT
PV
R
R1
RET
RETC
RETCN
S
S1
ST
STN
XORN
##################
# SFC qualifiers #
##################
D
DS
L
N
P
#R -> also an IL operator
#S -> also an IL operator
SD
SL
#####################
# Task initialisers #
#####################
PRIORITY
SINGLE
INTERVAL