Differentiate entries in Block Data with a flag in Fortran77 - fortran

Question

I am initializing a header struct in Fortran 77 in a BLOCK DATA . Whereas I have two versions of this *.f - file. One got an update with new functionality but the old version should be still supported.
The new version looks alike:
Block Data INIT_HS
Implicit None
C
Include 'hdr_str.inc'
C
Data (HDR_STRUC (I, NAVA), I = 1, 5)/
& CITY , AREA,
& LAT , LONG,
& ELEV,
& END/
C
Data (HDR_STRUC (I, NAVB), I = 1, 3)/
& CITY , CUST AREA,
& NAME , END/
C
Data HDR_STRING (CODE) /'CODE'/
Data HDR_STRING (ALT ) /'ALT'/
Data HDR_STRING (LAT) /'LAT'/
Data HDR_STRING (LON) /'LON'/
Data HDR_STRING (ACCL) /'ACCL'/
END
And in the old version some entries are not there:
Block Data INIT_HS
Implicit None
C
Include 'hdr_str.inc'
C
Data (HDR_STRUC (I, NAVA), I = 1, 3)/
& LAT , LONG,
& ELEV,
& END/
C
Data (HDR_STRUC (I, NAVB), I = 1, 2)/
& CITY , CUST AREA,
& END/
C
Data HDR_STRING (CODE) /'CODE'/
Data HDR_STRING (LAT) /'LAT'/
Data HDR_STRING (LON) /'LON'/
END
For the rest of the merged source code, I found a solution in handing over an argument when calling the executable:
DUMMY.exe VERSOLD
or:
DUMMY.exe VERSNEW
So I implemented a function setting a flag which version it is. For normal PROGRAM, SUBROUTINE etc. it is no issue but within this BLOCK DATA I can not just implement a CALL GETVERS ... IF (VERSOLD) THEN
I will get the following Error message from the compiler (gfortran -m32 -std=legacy -ffixed-line-length-none -c -g -fno-automatic -fno-second-underscore -finit-local-zero ) (..yes former g77..)
Error: Syntax error in DATA statement at (1)
Of course I could just implement a second BLOCK DATA with a different name.
I really wonder whether there is any other nice solution for this?