fix(asm): ensure platform can compile taint tracking sources [backport #5289 to 1.9] (#5312)

backport:  #5289

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/contributing.html#Release-Note-Guidelines)
are followed.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Author is aware of the performance implications of this PR as
reported in the benchmarks PR comment.

## Reviewer Checklist

- [x] Title is accurate.
- [x] No unnecessary changes are introduced.
- [x] Description motivates each change.
- [x] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Testing strategy adequately addresses listed risk(s).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] Release note makes sense to a user of the library.
- [x] Reviewer is aware of, and discussed the performance implications
of this PR as reported in the benchmarks PR comment.

Co-authored-by: Federico Mon <[email protected]>

Author: mabdinur

releasenotes/notes/fix-asm-taint-tracking-compilation-8c740752bd9df137.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    ASM: Resolves installation issues with compiling native code on Windows and unknown platforms.

setup.py

@@ -280,7 +280,7 @@ def get_exts_for(name):
             extra_compile_args=debug_compile_args,
         ),
     ]
-    if platform.system() != "Windows":
+    if platform.system() not in ("Windows", ""):
         ext_modules.append(
             Extension(
                 "ddtrace.appsec.iast._stacktrace",
@@ -298,7 +298,7 @@ def get_exts_for(name):
                     # Sort source files for reproducibility
                     sources=sorted(
                         glob.glob(
-                            os.path.join(HERE, "ddtrace", "appsec", "iast", "_taint_tracking", "**", "*.cpp"),
+                            os.path.join("ddtrace", "appsec", "iast", "_taint_tracking", "**", "*.cpp"),
                             recursive=True,
                         )
                     ),