Grep says the following:

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grep sqrt cuneiform_src/**/*.c*

cuneiform_src/Kern/leo/src/leo_stic.c:static uchar sqrt_tab[] = {
cuneiform_src/Kern/leo/src/leo_stic.c:            sqrt(vSticks[i].Mx*vSticks[i].Mx+vSticks[i].My*vSticks[i].My);
cuneiform_src/Kern/lns32/src/lbambuk.cpp:               max_width = (int)(ave_width + sqrt(dispers) + 1);
cuneiform_src/Kern/r35/src/r35.c:amax = sqrt(amax);
cuneiform_src/Kern/r35/src/r35.c:amax = sqrt(amax);
cuneiform_src/Kern/r35/src/r35.c:amax = sqrt(amax);
cuneiform_src/Kern/r35/src/r35.c:sq = sqrt (sq);
cuneiform_src/Kern/rblock/sources/c/ltwstrip.c:        Point.yAverage = (int) long_sqrt
cuneiform_src/Kern/rblock/sources/c/ltwstrip.c:        (int) long_sqrt ((int32_t) yAverageHystHeight / nHystColumns);
cuneiform_src/Kern/rblock/sources/c/scalar.c:static uchar sqrt_tab[] = {
cuneiform_src/Kern/rblock/sources/c/scalar.c:int16_t long_sqrt (uint32_t n)
cuneiform_src/Kern/rblock/sources/c/scalar.c: d = sqrt_tab[w]+1; d = d << sh; if ((d & 0xffff) == 0) return 0;
cuneiform_src/Kern/rblock/sources/c/seform.c:        (int) long_sqrt ((int32_t) (nSumTopDispersion
cuneiform_src/Kern/rblock/sources/c/seform.c:        (int) long_sqrt ((int32_t) (nSumBottomDispersion
cuneiform_src/Kern/rfrmt/sources/main/pagetree.cpp:  sig=(long)sqrt(sig/(float)(n+1));
cuneiform_src/Kern/rfrmt/sources/main/pagetree.cpp:    sig=(long)/*(float)*/sqrt(sig/(float)(n+1)); *sig1=(TYPE)sig;
cuneiform_src/Kern/rfrmt/sources/main/util_spl.cpp:  sig=(long)sqrt(sig/(float)(n+1));
cuneiform_src/Kern/rimage/sources/main/cribinarizator.cpp:	return (uchar)sqrt((((b * b) + (g * g) + (r * r)) / 70200 ) * 65025  );
cuneiform_src/Kern/rimage/sources/main/crrotator.cpp:	long double   fG      = sqrt( fNum * fNum + fDenum * fDenum );
cuneiform_src/Kern/rimage/sources/main/crrotator.cpp:	long double   fG      = sqrt( fNum * fNum + fDenum * fDenum );
cuneiform_src/Kern/rselstr/sources/src/chstr/rotate/rotate.cpp: D=sqrt(D);
cuneiform_src/Kern/rselstr/sources/src/cpp/scalar.cpp:static uchar sqrt_tab[] = { 0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4,
cuneiform_src/Kern/rselstr/sources/src/cpp/scalar.cpp:int16_t long_sqrt(uint32_t n) {
cuneiform_src/Kern/rselstr/sources/src/cpp/scalar.cpp:	d = sqrt_tab[w] + 1;
cuneiform_src/Kern/rselstr/sources/src/cpp/seform.cpp:        (int) long_sqrt ((int32_t) (nSumTopDispersion
cuneiform_src/Kern/rselstr/sources/src/cpp/seform.cpp:        (int) long_sqrt ((int32_t) (nSumBottomDispersion
cuneiform_src/Kern/rstr/src/dmbox.c: if ((SBOX.matrBOX.isq_rt = long_sqrt((*scalar)(mBOX,mBOX)))==0)
cuneiform_src/Kern/rstr/src/dms.c: if ((SBOX.matrBOX.isq_rt = long_sqrt((*scalar)(mBOX,mBOX)))==0)
cuneiform_src/Kern/rstr/src/dms.c: if ((SBOX.matrBOX.isq_rt = long_sqrt((*scalar)(mBOX,mBOX)))==0)
cuneiform_src/Kern/rstr/src/embbox.c: if ((norm = long_sqrt((*scalar)(vector, vector)))==0)  norm = 1;
cuneiform_src/Kern/rstr/src/scalar.c:static uchar sqrt_tab[] = {
cuneiform_src/Kern/rstr/src/scalar.c:int16_t long_sqrt (uint32_t n)
cuneiform_src/Kern/rstr/src/scalar.c: d = sqrt_tab[w]+1; d = d << sh; if ((d & 0xffff) == 0) return 0;
cuneiform_src/Kern/rverline/src/algoritm/verifyln.cpp:			Dist  = (int) sqrt ((double)Dist);
cuneiform_src/Kern/rverline/src/algoritm/verifyln.cpp:		Lent  = (int) sqrt ((double)Lent);
cuneiform_src/Kern/rverline/src/algoritm/verifyln.cpp:		Lent  = (int) sqrt ((double)Lent);
cuneiform_src/Kern/rverline/src/algoritm/verifyln.cpp:		Lent  = (int) sqrt ((double)Lent);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:		LentOld  = (int)sqrt ((double)LentOld);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:			LentNew  = (int)sqrt ((double)LentNew);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:		LentOld  = (int)sqrt ((double)LentOld);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:			LentNew  = (int)sqrt ((double)LentNew);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:	pLine->Len  = (int) sqrt ((double)pLine->Len);
cuneiform_src/Kern/usage/line_vp_2_am.cpp:	pLine->Len  = (int) sqrt ((double)pLine->Len);
cuneiform_src/Kern/usage/line_vp_util.cpp:			Lent  = (int) sqrt ((double)Lent);
cuneiform_src/Kern/usage/line_vp_util.cpp:			Lent  = (int) sqrt ((double)Lent);

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According to this, leo has a sqrt_tab so it should probably use that. Other modules that use sqrt include r35, rfrmt, rimage, rverline, and usage. Why don't they give the link error? Is there some symbol resolution/linker magic going on?