As stated by srcpkgs/flightgear/patches/musl-fenv.patch:
"""
Simply disabling the code which enables floating point exceptions
is probably wrong, but I don't have a replacement for the
non-posix functions fegetexcept(3) and feenableexcept(3).
"""

--- src/OSD/OSD_signal.cxx.orig
+++ src/OSD/OSD_signal.cxx
@@ -645,7 +645,7 @@
 
 #include <signal.h>
 
-#if !defined(__ANDROID__) && !defined(__QNX__)
+#if !defined(__ANDROID__) && !defined(__QNX__) && defined(__GLIBC__)
   #include <sys/signal.h>
 #endif
 
@@ -687,7 +687,7 @@
   // cout << "OSD::Handler: signal " << (int) theSignal << " occured inside a try block " <<  endl ;
   if ( ADR_ACT_SIGIO_HANDLER != NULL )
     (*ADR_ACT_SIGIO_HANDLER)() ;
-#ifdef __linux__
+#if defined(__linux__) && defined(__GLIBC__)
   if (fFltExceptions)
     feenableexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW);
     //feenableexcept (FE_INVALID | FE_DIVBYZERO);
@@ -805,7 +805,7 @@
   (void)theSignal; // silence GCC warnings
   (void)theContext;
 
-#ifdef __linux__
+#if defined(__linux__) && defined(__GLIBC__)
   if (fFltExceptions)
     feenableexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW);
     //feenableexcept (FE_INVALID | FE_DIVBYZERO);
@@ -892,14 +892,18 @@
 #endif
     }
 #elif defined (__linux__)
+#if defined(__GLIBC__)
     feenableexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW);
+#endif
     fFltExceptions = Standard_True;
 #endif
   }
   else
   {
 #if defined (__linux__)
+#if defined(__GLIBC__)
     fedisableexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW);
+#endif
     fFltExceptions = Standard_False;
 #endif
   }