[gcc r11-10383] nvptx: In 'STARTFILE_SPEC', fix 'crt0.o' for '-mmainkernel'

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:4805d602d8dd25c10d1d8f30daa8a2eed0aed108

commit r11-10383-g4805d602d8dd25c10d1d8f30daa8a2eed0aed108
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Fri Nov 18 23:57:52 2022 +0100

    nvptx: In 'STARTFILE_SPEC', fix 'crt0.o' for '-mmainkernel'
    
    A recent nvptx-tools change: commit 886a95faf66bf66a82fc0fe7d2a9fd9e9fec2820
    "ld: Don't search for input files in '-L'directories" (of
    <https://github.com/MentorEmbedded/nvptx-tools/pull/38>
    "Match standard 'ld' "search" behavior") in GCC/nvptx target testing
    generally causes linking to fail with:
    
        error opening crt0.o
        collect2: error: ld returned 1 exit status
        compiler exited with status 1
    
    Indeed per GCC '-v' output, there is an undecorated 'crt0.o' on the linker
    ('collect2') command line:
    
         [...]/build-gcc/./gcc/collect2 -o [...] crt0.o [...]
    
    This is due to:
    
        gcc/config/nvptx/nvptx.h:#define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
    
    ..., and the fix, as used by numerous other GCC targets, is to instead use
    'crt0.o%s'; for '%s' means, per 'gcc/gcc.cc', "The Specs Language":
    
         %s     current argument is the name of a library or startup file of some sort.
                Search for that file in a standard list of directories
                and substitute the full name found.
    
    With that, we get the expected path to 'crt0.o'.
    
            gcc/
            * config/nvptx/nvptx.h (STARTFILE_SPEC): Fix 'crt0.o' for
            '-mmainkernel'.
    
    (cherry picked from commit dda43e1ef0c9f6c32ad022d3a08ce7651e42a129)

Diff:
---
 gcc/config/nvptx/nvptx.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 3273ad86673..f1965d91fdd 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -27,7 +27,7 @@
 
 /* Run-time Target.  */
 
-#define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
+#define STARTFILE_SPEC "%{mmainkernel:crt0.o%s}"
 
 /* Default needs to be in sync with default for misa in nvptx.opt.
    We add a default here to work around a hard-coded sm_30 default in