checksrc: exclude generated bundle files to avoid race condition

Necessary to catch rare cases when `checksrc` hits these files when they
are not populated yet:
```
./curltool_unity.c:1:1: error: Missing copyright statement (COPYRIGHT)
 ^
```
https://github.com/curl/curl/actions/runs/12995546740/job/36242556713?pr=16094#step:37:123

Follow-up to 71cf0d1 curl#14772
Closes curl#16102

lib/Makefile.am

@@ -143,9 +143,10 @@ CS_1 =
 CS_ = $(CS_0)
 
 checksrc:
-	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir)    \
-	-W$(srcdir)/curl_config.h $(srcdir)/*.[ch] $(srcdir)/vauth/*.[ch]   \
-	$(srcdir)/vtls/*.[ch] $(srcdir)/vquic/*.[ch] $(srcdir)/vssh/*.[ch])
+	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir)         \
+	  -W$(srcdir)/libcurl_unity.c -W$(srcdir)/curl_config.h $(srcdir)/*.[ch] \
+	  $(srcdir)/vauth/*.[ch] $(srcdir)/vtls/*.[ch] $(srcdir)/vquic/*.[ch]    \
+	  $(srcdir)/vssh/*.[ch])
 
 if DEBUGBUILD
 # for debug builds, we scan the sources on all regular make invokes

src/Makefile.am

@@ -188,6 +188,8 @@ checksrc:
 	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir) \
 	  -W$(srcdir)/$(HUGE) \
 	  -W$(srcdir)/$(CA_EMBED_CSOURCE) \
+	  -W$(srcdir)/curltool_unity.c \
+	  -W$(srcdir)/libcurltool_unity.c \
 	  $(srcdir)/*.[ch])
 
 if DEBUGBUILD

tests/libtest/Makefile.am

@@ -118,8 +118,11 @@ CS_0 = @echo "  RUN     " $@;
 CS_1 =
 CS_ = $(CS_0)
 
+# ignore generated C files since they play by slightly different rules!
 checksrc:
-	$(CHECKSRC)@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir) $(srcdir)/*.[ch]
+	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir) \
+	  -W$(srcdir)/libtest_bundle.c \
+	  $(srcdir)/*.[ch])
 
 if DEBUGBUILD
 # for debug builds, we scan the sources on all regular make invokes

tests/unit/Makefile.am

@@ -74,5 +74,8 @@ CS_0 = @echo "  RUN     " $@;
 CS_1 =
 CS_ = $(CS_0)
 
+# ignore generated C files since they play by slightly different rules!
 checksrc:
-	$(CHECKSRC)@PERL@ $(top_srcdir)/scripts/checksrc.pl $(srcdir)/*.[ch]
+	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir) \
+	  -W$(srcdir)/unit_bundle.c \
+	  $(srcdir)/*.[ch])