Remove generate_dsym argument

[lionel-]

Follow up for #2598

It's not necessary to generate a dSYM file if you use build = FALSE.

The problem with build = TRUE is that if you're not generating dSYM files, the linker inserts paths to object files that contain the DWARF debug info and these paths are pointing to dangling temporary locations:

> nm -a /Users/lionel/R/Library/4.4-aarch64/rlang/libs/rlang.so | grep OSO
0000000067ef7d43 - 00 0001   OSO /private/tmp/RtmpIM0xjp/R.INSTALLe9c020cfb3cd/rlang/src/capture.o
0000000067ef7d43 - 00 0001   OSO /private/tmp/RtmpIM0xjp/R.INSTALLe9c020cfb3cd/rlang/src/internal.o
0000000067ef7d43 - 00 0001   OSO /private/tmp/RtmpIM0xjp/R.INSTALLe9c020cfb3cd/rlang/src/rlang.o
0000000067ef7d43 - 00 0001   OSO /private/tmp/RtmpIM0xjp/R.INSTALLe9c020cfb3cd/rlang/src/version.o

The workaround implemented in the linked PR is to generate a dSYM file that contains the DWARF info. But this debug info itself points to source files in the dangling temporary directory, forcing the user to remap these files in the debugger, which is quite cumbersome.

With build = FALSE the package is installed directly from source so the recorded paths to object files are correct:

> nm -a /Users/lionel/R/Library/4.4-aarch64/rlang/libs/rlang.so | grep OSO
0000000067ed4ae1 - 00 0001   OSO /Users/lionel/Sync/Projects/R/r-lib/rlang/src/capture.o
0000000067ef785b - 00 0001   OSO /Users/lionel/Sync/Projects/R/r-lib/rlang/src/internal.o
0000000067ef785b - 00 0001   OSO /Users/lionel/Sync/Projects/R/r-lib/rlang/src/rlang.o
0000000067ed4ae1 - 00 0001   OSO /Users/lionel/Sync/Projects/R/r-lib/rlang/src/version.o

There is no need to generate a dSYM file in that case. The only advantage of that file is that you are allowed to delete the object files in the source repo and still preserve full debug information but in practice I think most of us keep their src directory dirty.

Generating these files gets in the way of various dev workflows since they are not ignored by default so it's better not to have to deal with those. For instance I saw that NOTE during check:

N  checking if this is a source package ...
   Found the following apparent object files/libraries:
     src/rlang.so.dSYM/Contents/Resources/DWARF/rlang.so
   Object files/libraries should not be included in a source package.

[gaborcsardi]

Thanks!