Was this a scripted change? Would you mind saying which script you ran exactly? Thanks!

I used "search and replace in files" in my default IDE Eclipse CDT.
However, simple commands, like sed -i -e 's@^#include <config\.h>$@#include "config.h"@' */*.{c,h} */*/*.{c,h} */*/*/*.{c,h} */*/*/*/*.{c,h} or find . -type f \( -name '*.c' -o -name '*.h' \) -exec sed -i -e 's@^#include <config\.h>$@#include "config.h"@' {} + can do the same (assuming your sed supports non-portable -i, like GNU sed).

I used "search and replace in files" in my default IDE Eclipse CDT. However, simple commands, like sed -i -e 's@^#include <config\.h>$@#include "config.h"@' */*.{c,h} */*/*.{c,h} */*/*/*.{c,h} */*/*/*/*.{c,h} or find . -type f \( -name '*.c' -o -name '*.h' \) -exec sed -i -e 's@^#include <config\.h>$@#include "config.h"@' {} + can do the same (assuming your sed supports non-portable -i, like GNU sed).

Yup, I'd have done

$ find . -type f | grep '\.[ch]$' | xargs sed -i 's/^#include <config\.h>$/#include "config.h"/';

It is always good to know how scripted changes have been applied exactly, in case it misses some cases accidentally.

Yup, I'd have done

$ find . -type f | grep '\.[ch]$' | xargs sed -i 's/^#include <config\.h>$/#include "config.h"/';

It is always good to know how scripted changes have been applied exactly, in case it misses some cases accidentally.

Sed command can be further improved to really catch everything:
sed -i -Ee 's/^([ ]*)#([ ]*)include <config\.h>/#\2include "config.h/', where [ ] should be [ space tab ].
😄