During build of 33f93b139ccbab42282bd36e81f301699320ae58, I get the following warnings, which seem suspicious:
```
* Generating sql_code.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_1.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_2pc.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_adm.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_auto.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_dav.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_dbp.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_ddk.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_imsg.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_pldbg.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_repl.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_sparql.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_sys.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_uddi.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_vad.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_vdb.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_ws.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
```
Warnings about unknown regexp operator during build
This is a GitHub Issue
repo:virtuoso-opensource
owner:openlink
Title : Warnings about unknown regexp operator during build
Issue date:

--- start body ---
During build of 33f93b139ccbab42282bd36e81f301699320ae58, I get the following warnings, which seem suspicious:
```
* Generating sql_code.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_1.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_2pc.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_adm.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_auto.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_dav.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_dbp.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_ddk.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_imsg.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_pldbg.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_repl.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_sparql.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_sys.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_uddi.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_vad.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_vdb.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
* Generating sql_code_ws.c using GNU Awk 5.1.0, API: 3.0 (GNU MPFR 4.1.0, GNU MP 6.2.1)
gawk: ./sql_to_c.awk:109: warning: regexp escape sequence `\ ' is not a known regexp operator
gawk: ./sql_to_c.awk:500: warning: regexp escape sequence `\"' is not a known regexp operator
```
--- end body ---
